Silicon nitride film and preparation method and application thereof
Through atomic layer deposition and plasma technology, a complex of metal inorganic salts and amino acids is introduced to prepare a carbon-metal co-doped silicon nitride film, which solves the problem of difficult control of the thickness of silicon nitride film and low density in the prior art, and realizes the preparation of high-density and good adhesion silicon nitride films, which are suitable for semiconductor and microelectronic applications.
Patent Information
- Application Number
- CN202510264156.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-06
- Publication Date
- 2025-06-06
AI Technical Summary
The silicon nitride film prepared by the existing silane chemical deposition method has problems such as difficulty in controlling the thickness, low density, reduced insulation and reduced adhesion.
The method of atomic layer deposition and binding plasma is adopted to introduce complexes of metal inorganic salts and amino acids to regulate the content of carbon and metal elements, control the growth process of the film, and prepare a carbon-metal co-doped silicon nitride film.
A thinner and high-density silicon nitride film is obtained, which improves its insulation and adhesion and is suitable for semiconductor materials and microelectronics fields.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of semiconductor materials, and in particular relates to a silicon nitride film and a preparation method and application thereof. Background Art
[0002] In recent years, due to the growing demand for semiconductor devices and integrated circuits, silicon nitride films with excellent mechanical, optical and electrical properties are one of the indispensable materials in the semiconductor industry. Market research reports predict that the global silicon nitride film market size is expected to continue to grow. By 2028, the global silicon nitride film market size will reach approximately US$993.3 million.
[0003] When silicon nitride film is used as an insulating layer, mask layer, and passivation layer in semiconductor manufacturing, it can effectively improve the stability and integration of devices. With the advancement of deposition technology, the quality and performance of silicon nitride film have been continuously improved, further promoting its application in microelectronic devices. There are many methods for preparing silicon nitride. For example, the direct nitridation method is to react silicon powder with nitrogen at high temperature (1300-1500°C) to produce silicon nitride; silicon nitride can also be prepared by burning a mixture of silicon dioxide and carbon in nitrogen containing a small amount of hydrogen. Chemical vapor deposition (CVD) technology uses silane and ammonia as precursor gases to react at high temperature (600-900°C) to produce silicon nitride film. This method is suitable for preparing high-quality films and is widely used in microelectronics and optoelectronic devices. Silane, as the most commonly used precursor molecule in the preparation of silicon nitride film by chemical vapor deposition, has higher activity, can be deposited at lower temperatures, and has a faster deposition rate, which is an important advantage for depositing silicon nitride films on temperature-sensitive devices.
[0004] However, silane generates residual stress during the deposition reaction. Excessive tensile stress or compressive stress can easily lead to film cracking. The film thickness formed by conventional silane deposition is difficult to control. As the number of coatings increases after chamber cleaning, it is easy to deposit a thicker and less dense film, resulting in reduced insulation and reduced adhesion between the film and the substrate. Due to the above problems in the silicon nitride film prepared by the existing silane chemical deposition method, the silicon nitride film has great limitations when used as an electrical insulation layer, mask layer, passivation layer, etc. of semiconductor devices. Summary of the invention
[0005] One of the purposes of the present invention is to provide a method for preparing a silicon nitride film in order to address the problem that the silicon nitride film prepared by the existing method has a high thickness and a low density, which leads to reduced insulation of the film and reduced adhesion between the film and the substrate.
[0006] Specifically, the preparation method includes the following steps: S1. placing a substrate in a reaction chamber, introducing an aminosilane precursor into the reaction chamber by atomic layer deposition and chemically adsorbing it with the substrate to obtain a first reaction product; S2. introducing a complex of a metal inorganic salt and an amino acid into the reaction chamber by atomic layer deposition and performing a first reaction with the first reaction product to obtain a second reaction product; S3. introducing a nitrogen source plasma gas into the reaction chamber and performing a second reaction with the second reaction product to obtain a carbon-metal co-doped silicon nitride layer; S4. repeating steps S1 to S3 at least twice in sequence to obtain a carbon-metal co-doped silicon nitride film.
[0007] In a preferred embodiment, the aminosilane precursor comprises at least one of the compounds represented by formula (1) to (4),
[0008]
[0009] In formulas (1) to (4), R 1 ~R 20 are each independently a hydrogen atom or a C 1 ~C 5 of alkyl.
[0010] In a preferred embodiment, in step S1, the method of introducing an aminosilane precursor into a reaction chamber by atomic layer deposition and chemically adsorbing the aminosilane precursor onto a substrate comprises: using gas I as a carrier gas in a pulsed form to introduce the aminosilane precursor into the reaction chamber to contact the substrate for chemical adsorption to obtain a first reaction product.
[0011] In a preferred embodiment, in step S1, the gas I is selected from at least one of nitrogen, argon, helium and krypton.
[0012] In a preferred embodiment, in step S1, the flow rate of the gas I is 100-400 sccm.
[0013] In a preferred embodiment, in step S1, the aminosilane precursor is in contact with the substrate for chemical adsorption for 3 to 15 seconds.
[0014] In a preferred embodiment, in step S2, the method of introducing a complex of a metal inorganic salt and an amino acid into a reaction chamber by atomic layer deposition and performing a first reaction with a first reaction product includes: using gas II in the form of a pulse to introduce the complex of a metal inorganic salt and an amino acid into the reaction chamber to contact with the first reaction product to perform a first reaction to obtain a second reaction product.
[0015] In a preferred embodiment, in step S2, the gas II is selected from at least one of nitrogen, argon, helium and krypton.
[0016] In a preferred embodiment, in step S2, the flow rate of gas II is 100-400 sccm.
[0017] In a preferred embodiment, in step S2, the time for the first reaction of the complex of the metal inorganic salt and the amino acid in contact with the first reaction product is 3 to 15 seconds.
[0018] In a preferred embodiment, the metal inorganic salt is selected from at least one of aluminum chloride, gallium chloride, indium chloride and thallium chloride.
[0019] In a preferred embodiment, the amino acid is selected from at least one of alanine, aspartic acid, isoleucine, leucine, lysine, glutamic acid and glutamine.
[0020] In a preferred embodiment, in step S3, the nitrogen source plasma gas is nitrogen plasma gas and / or ammonia plasma.
[0021] In a preferred embodiment, in step S3, the flow rate of the nitrogen source plasma gas is 100-400 sccm.
[0022] In a preferred embodiment, in step S3, the time for the second reaction between the nitrogen source plasma gas and the second reaction product is 20 to 60 seconds.
[0023] In a preferred embodiment, in steps S1 to S3, the temperature of the reaction chamber is independently 200 to 500° C., and the pressure is 150 to 500 Pa.
[0024] A second object of the present invention is to provide a silicon nitride film prepared by the above method.
[0025] In a preferred embodiment, the thickness of the silicon nitride film is
[0026] The third object of the present invention is to provide the application of the above silicon nitride film in the semiconductor industry and / or microelectronics field.
[0027] Beneficial effect: In the method for preparing the silicon nitride film provided by the present invention, a complex of a metal inorganic salt and an amino acid is introduced in the process of forming the silicon nitride film by adopting an atomic layer deposition combined with a plasma method to regulate the content of carbon and metal elements in the obtained film, and to control the growth process of the film, thereby obtaining a carbon-metal co-doped silicon nitride film with high density and thinner thickness. The silicon nitride film has high quality and good adhesion to the substrate, thereby improving the insulation ability, and can be well applied to the fields of semiconductor materials and microelectronics, and has good application prospects. DETAILED DESCRIPTION
[0028] The preparation method of the silicon nitride film provided by the present invention comprises the following steps: S1. placing a substrate in a reaction chamber, introducing an aminosilane precursor into the reaction chamber by atomic layer deposition and chemically adsorbing it with the substrate to obtain a first reaction product; S2. introducing a complex of a metal inorganic salt and an amino acid into the reaction chamber by atomic layer deposition and performing a first reaction with the first reaction product to obtain a second reaction product; S3. introducing a nitrogen source plasma gas into the reaction chamber and performing a second reaction with the second reaction product to obtain a carbon-metal co-doped silicon nitride layer; S4. repeating steps S1 to S3 at least twice in sequence to obtain a carbon-metal co-doped silicon nitride film.
[0029] In the present invention, the substrate is a type of material commonly used in the semiconductor industry and the field of microelectronics. Those skilled in the art can make adaptive choices from the prior art according to actual needs. The present invention does not impose any particular limitation. Specific examples include but are not limited to: at least one of silicon wafers, quartz, glass and resin.
[0030] In the present invention, the aminosilane precursor preferably comprises at least one of the compounds represented by formulas (1) to (4),
[0031]
[0032] In formulas (1) to (4), R 1 ~R 20 are each independently a hydrogen atom or a C 1 ~C 5 The C 1 ~C 5 Specific examples of the alkyl group include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 1,2-dimethylpropyl, and 1-ethylpropyl.
[0033] Further, specific examples of the aminosilane precursor include, but are not limited to: at least one of methylaminosilane, ethyldiaminosilane, n-propylaminosilane, isopropylaminosilane, n-butylaminosilane, isobutylaminosilane, tert-butylaminosilane, bis(methylamino)silane, bis(dimethylamino)silane, bis(diethylamino)silane, bis(n-propylamino)silane, bis(isopropylamino)silane, bis(n-butylamino)silane, bis(isobutylamino)silane, bis(tert-butylamino)silane, tris(methylamino)silane, tris(ethylamino)silane, tris(n-propylamino)silane, tris(isopropylamino)silane, tris(n-butylamino)silane, tris(isobutylamino)silane, tris(tert-butylamino)silane, tetrakis(methylamino)silane, and tetrakis(ethylamino)silane.
[0034] In the present invention, in steps S1 to S3, when the aminosilane precursor contacts the substrate for chemical adsorption, or when the complex of the metal inorganic salt and the amino acid contacts the first reaction product for the first reaction, or when the nitrogen source plasma gas contacts the second reaction product for the second reaction, the temperature of the reaction chamber is preferably independently 200 to 500°C, such as 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C or any value therebetween; the pressure is preferably 150 to 500Pa, such as 150Pa, 200Pa, 250Pa, 300Pa, 350Pa, 400Pa, 450Pa, 500Pa or any value therebetween.
[0035] In the present invention, in steps S1 and S2, the atomic layer deposition refers to a technique of using a heat source to decompose a precursor substance and deposit it on a substrate to form a single-layer structure. More specifically, the process and conditions for forming the first reactant or the second reactant by atomic layer deposition in steps S1 and S2 may be completely the same, partially the same, or completely different.
[0036] In the present invention, in step S1, the method of introducing an aminosilane precursor into a reaction chamber by atomic layer deposition and chemically adsorbing the aminosilane precursor with a substrate specifically includes: using gas I as a carrier gas in a pulsed form to introduce the aminosilane precursor into the reaction chamber to contact the substrate for chemical adsorption to obtain a first reaction product.
[0037] Furthermore, in step S1, specific examples of the gas I include, but are not limited to, at least one of nitrogen, argon, helium, and krypton.
[0038] Further, in step S1, the flow rate of the gas I is preferably 100-400 sccm, such as 100 sccm, 150 sccm, 200 sccm, 250 sccm, 300 sccm, 350 sccm, 400 sccm or any value therebetween.
[0039] Furthermore, in step S1, the time for the aminosilane precursor to be in contact with the substrate for chemical adsorption is preferably 3 to 15 seconds, such as 3 seconds, 5 seconds, 8 seconds, 10 seconds, 12 seconds, 15 seconds or any value therebetween.
[0040] Furthermore, step S1 may further include: introducing gas I to purge the first reaction product to remove unreacted aminosilane precursor, further improving the purity and quality of the film. The purge time is preferably 30 to 80 seconds, such as 30 seconds, 40 seconds, 50 seconds, 60 seconds, 70 seconds, 80 seconds or any value therebetween.
[0041] In the present invention, in step S2, the method of introducing the complex of metal inorganic salt and amino acid into the reaction chamber by atomic layer deposition and performing a first reaction with the first reaction product specifically includes: using gas II in the form of pulses to introduce the complex of metal inorganic salt and amino acid into the reaction chamber to contact with the first reaction product to perform a first reaction, thereby obtaining a second reaction product.
[0042] Furthermore, in step S2, specific examples of the gas II include, but are not limited to, at least one of nitrogen, argon, helium, and krypton.
[0043] Further, in step S2, the flow rate of the gas II is preferably 100-400 sccm, such as 100 sccm, 150 sccm, 200 sccm, 250 sccm, 300 sccm, 350 sccm, 400 sccm or any value therebetween.
[0044] Furthermore, in step S2, the time for the complex of the metal inorganic salt and the amino acid to contact the first reaction product for the first reaction is preferably 3 to 15 seconds, such as 3 seconds, 5 seconds, 8 seconds, 10 seconds, 12 seconds, 15 seconds or any value therebetween.
[0045] Furthermore, step S2 may also include: introducing gas II to purge the second reaction product to remove unreacted metal inorganic salt and amino acid complexes, further improving the purity and quality of the film. The purge time is preferably 30 to 80 seconds, such as 30 seconds, 40 seconds, 50 seconds, 60 seconds, 70 seconds, 80 seconds or any value therebetween.
[0046] In the present invention, the complex of the metal inorganic salt and the amino acid can be purchased or obtained by a coordination reaction between the metal inorganic salt and the amino acid.
[0047] In a specific embodiment, the coordination reaction is preferably carried out in the presence of a solvent. The conditions of the coordination reaction include: dissolving the metal inorganic salt and the amino acid in a solvent, adjusting the pH to 6.5-8, heating to 40-80°C under condensation reflux and stirring for 2-10 hours, adding ethanol and / or acetone after cooling, and the resulting precipitated product is the complex of the metal inorganic salt and the amino acid.
[0048] Furthermore, the molar ratio of the metal inorganic salt to the amino acid is preferably 1:(1-3), such as 1:1, 1:1.5, 1:2, 1:2.5, 1:3 or any value therebetween.
[0049] Furthermore, the solvent is a conventional solvent used in the prior art for preparing complexes of metal inorganic salts and amino acids, which can be determined according to the metal inorganic salts and amino acids actually used, and specifically can be water or a mixed solvent containing water and an organic solvent.
[0050] In the present invention, the metal inorganic salt is a compound formed by one of metal ions such as aluminum, gallium, indium, thallium and the like and an inorganic anion, and specific examples thereof include but are not limited to at least one of aluminum chloride, gallium chloride, indium chloride and thallium chloride.
[0051] In the present invention, specific examples of the amino acid include but are not limited to: at least one of alanine, aspartic acid, isoleucine, leucine, lysine, glutamic acid, and glutamine, and more preferably at least one of alanine, isoleucine, leucine, and lysine. This is more conducive to further regulating the growth process of the film, improving the uniformity of the grown film, and forming a thinner high-quality film.
[0052] In the present invention, in step S3, the nitrogen source plasma gas is preferably nitrogen plasma gas and / or ammonia plasma.
[0053] Further, in step S3, the flow rate of the nitrogen source plasma gas is preferably 100-400 sccm, such as 100 sccm, 150 sccm, 200 sccm, 250 sccm, 300 sccm, 350 sccm, 400 sccm or any value therebetween.
[0054] Further, in step S3, the time for the second reaction between the nitrogen source plasma gas and the second reaction product is preferably 20 to 60 seconds, such as 20 seconds, 30 seconds, 40 seconds, 50 seconds, 60 seconds or any value therebetween.
[0055] Furthermore, step S3 may also include: introducing gas III to purge the carbon-metal co-doped silicon nitride layer to remove unreacted components and further improve the purity and quality of the film. The purge time is preferably 30 to 80 seconds, such as 30 seconds, 40 seconds, 50 seconds, 60 seconds, 70 seconds, 80 seconds or any value therebetween.
[0056] Furthermore, in step S3, specific examples of the gas III include, but are not limited to, at least one of nitrogen, argon, helium, and krypton.
[0057] Further, in step S3, the flow rate of the gas III is preferably 100-400 sccm, such as 100 sccm, 150 sccm, 200 sccm, 250 sccm, 300 sccm, 350 sccm, 400 sccm or any value therebetween.
[0058] The present invention also provides a silicon nitride film, which is specifically prepared by the above-mentioned method for preparing the silicon nitride film.
[0059] Furthermore, the thickness of the silicon nitride film is preferably like or any value in between.
[0060] The present invention also provides application of the silicon nitride film in the field of semiconductor materials and / or microelectronics.
[0061] In addition, the terms "first", "second", "Ⅰ", "Ⅱ", and "Ⅲ" are only for the purpose of convenience of description and should not be understood as special limitations on the type or quantity of technical features.
[0062] The present invention will be described in detail below by specific examples, and the examples of the embodiments are intended to be used to explain the present invention and should not be construed as limiting the present invention. If no specific techniques or conditions are specified in the embodiments, the techniques or conditions described in the literature in this area or the product instructions are used. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.
[0063] Preparation Example 1
[0064] Aluminum chloride and lysine were weighed in a molar ratio of 1:2 and dissolved in water, and sodium hydroxide was added to adjust the pH to 7-7.5, and the temperature was raised to 60°C. The mixture was stirred for reaction for 4 hours under condensation reflux conditions, and ethanol was added to precipitate after cooling. The complex of aluminum chloride and lysine was obtained after filtering, washing and drying.
[0065] Preparation Example 2
[0066] Aluminum chloride and alanine were weighed in a molar ratio of 1:2 and dissolved in water, and sodium hydroxide was added to adjust the pH to 6.5-7, and the temperature was raised to 40°C. The mixture was stirred for reaction for 4 hours under condensation reflux conditions, and ethanol was added to precipitate after cooling. The complex of aluminum chloride and alanine was obtained after filtering, washing and drying.
[0067] Preparation Example 3
[0068] Gallium chloride and isoleucine were weighed in a molar ratio of 1:2 and dissolved in water, sodium hydroxide was added to adjust the pH to 7.5-8, the temperature was raised to 80°C, and the reaction was stirred for 4 hours under condensation reflux conditions. After cooling, ethanol was added to precipitate, and the complex of gallium chloride and isoleucine was obtained after filtering, washing and drying.
[0069] Preparation Example 4
[0070] Aluminum chloride and aspartic acid were weighed in a molar ratio of 1:2 and dissolved in water, and sodium hydroxide was added to adjust the pH to 7-7.5, and the temperature was raised to 60°C. The mixture was stirred for reaction for 4 hours under condensation reflux conditions, and ethanol was added to precipitate after cooling. The complex of aluminum chloride and aspartic acid was obtained after filtering, washing and drying.
[0071] Preparation Example 5
[0072] Aluminum chloride and glutamic acid are weighed in a molar ratio of 1:2 and dissolved in water, sodium hydroxide is added to adjust the pH to 7.5-8, the temperature is raised to 80°C, and the reaction is stirred for 4 hours under condensation reflux conditions. After cooling, ethanol is added to precipitate, and the complex of aluminum chloride and glutamic acid is obtained after filtering, washing and drying.
[0073] Example 1
[0074] This embodiment is used to illustrate a method for preparing a silicon nitride film, which specifically includes the following steps:
[0075] S1. placing a substrate in a reaction chamber of an atomic layer deposition device, setting the reaction chamber temperature to 400°C and the pressure to 150 Pa, then introducing nitrogen gas at a flow rate of 250 sccm as a carrier gas, continuously introducing diisopropylaminosilane into the reaction chamber in a pulsed form and chemically adsorbing the diisopropylaminosilane with the substrate for 8 seconds to obtain a first reactant, and continuing to introduce nitrogen gas for 50 seconds for purging to remove unadsorbed diisopropylaminosilane;
[0076] S2. A nitrogen gas with a flow rate of 250 sccm is introduced as a carrier gas, and the aluminum chloride and lysine complex obtained in Preparation Example 1 is continuously introduced into the reaction chamber in the form of pulses and contacted with the first reaction product for a first reaction for 8 seconds to obtain a second reactant, and nitrogen gas is continuously introduced for 50 seconds for purging to remove the aluminum chloride and lysine complex that has not been adsorbed;
[0077] S3. The nitrogen plasma gas is continuously introduced into the reaction chamber at a flow rate of 200 sccm and reacts with the second reaction product for 50 seconds to obtain a carbon-aluminum co-doped silicon nitride layer;
[0078] S4. After repeating steps S1 to S3 200 times, a film with a thickness of Carbon-aluminum co-doped silicon nitride films.
[0079] Example 2
[0080] This embodiment is used to illustrate a method for preparing a silicon nitride film, which specifically includes the following steps:
[0081] S1. Place the substrate in the reaction chamber of the atomic layer deposition equipment, set the reaction chamber temperature to 500°C and the pressure to 150Pa, then introduce nitrogen gas with a flow rate of 250sccm as a carrier gas, continuously introduce triisopropylaminosilane into the reaction chamber in the form of pulses and chemically adsorb it with the substrate for 8s to obtain the first reactant, and continue to introduce nitrogen gas for 50s for purging to remove the unadsorbed diisopropylaminosilane;
[0082] S2. A nitrogen gas with a flow rate of 250 sccm is introduced as a carrier gas, and the aluminum chloride and alanine complex obtained in Preparation Example 2 is continuously introduced into the reaction chamber in the form of pulses and contacted with the first reaction product for a first reaction for 8 seconds to obtain a second reactant, and nitrogen gas is continuously introduced for 50 seconds for purging to remove the aluminum chloride and alanine complex that has not been adsorbed;
[0083] S3. The nitrogen plasma gas is continuously introduced into the reaction chamber at a flow rate of 200 sccm and reacts with the second reaction product for 50 seconds to obtain a carbon-aluminum co-doped silicon nitride layer;
[0084] S4. After repeating steps S1 to S3 200 times, a film with a thickness of Carbon-aluminum co-doped silicon nitride films.
[0085] Example 3
[0086] This embodiment is used to illustrate a method for preparing a silicon nitride film, which specifically includes the following steps:
[0087] S1. placing a substrate in a reaction chamber of an atomic layer deposition apparatus, setting the reaction chamber temperature to 300°C and the pressure to 450Pa, then introducing nitrogen gas at a flow rate of 250sccm as a carrier gas, continuously introducing isopropylaminosilane into the reaction chamber in a pulsed form and chemically adsorbing the isopropylaminosilane with the substrate for 8s to obtain a first reactant, and continuing to introduce nitrogen gas for 50s for purging to remove unadsorbed diisopropylaminosilane;
[0088] S2. A nitrogen gas with a flow rate of 250 sccm is introduced as a carrier gas, and the gallium chloride and isoleucine complex obtained in Preparation Example 3 is continuously introduced into the reaction chamber in the form of pulses and contacted with the first reaction product for a first reaction for 8 seconds to obtain a second reactant, and nitrogen gas is continued to be introduced for 50 seconds for purging to remove the gallium chloride and isoleucine complex that has not been adsorbed;
[0089] S3. The nitrogen plasma gas is continuously introduced into the reaction chamber at a flow rate of 200 sccm and reacts with the second reaction product for 50 seconds to obtain a carbon-gallium co-doped silicon nitride layer;
[0090] S4. After repeating steps S1 to S3 200 times, a film with a thickness of Carbon-aluminum co-doped silicon nitride films.
[0091] Example 4
[0092] A silicon nitride film was prepared according to the method of Example 1, except that the aluminum chloride and aspartic acid complex obtained in Preparation Example 4 was used in step S2 instead of the aluminum chloride and lysine complex, and the other conditions were the same as those in Example 1, thereby preparing a silicon nitride film with a thickness of Carbon-aluminum co-doped silicon nitride films.
[0093] Example 5
[0094] A silicon nitride film was prepared according to the method of Example 1, except that the aluminum chloride and glutamic acid complex obtained in Preparation Example 5 was used in step S2 instead of the aluminum chloride and lysine complex, and the other conditions were the same as those in Example 1, thereby preparing a silicon nitride film with a thickness of Carbon-aluminum co-doped silicon nitride films.
[0095] Comparative Example 1
[0096] A reference silicon nitride film was prepared according to the method of Example 1, except that step S2 was not performed. The other conditions were the same as those of Example 1. Thus, a silicon nitride film with a thickness of Reference silicon nitride film.
[0097] Comparative Example 2
[0098] A reference silicon nitride film was prepared according to the method of Example 1, except that tri(dimethylamino)aluminum was used in step S2 instead of the complex of aluminum chloride and lysine, and the other conditions were the same as those of Example 1. Thus, a silicon nitride film with a thickness of 1000 nm was prepared on the substrate. Reference silicon nitride film.
[0099] Comparative Example 3
[0100] A reference silicon nitride film was prepared according to the method of Example 1, except that aluminum chloride was used in step S2 instead of the complex of aluminum chloride and lysine. The other conditions were the same as those of Example 1. Thus, a silicon nitride film with a thickness of Reference silicon nitride film.
[0101] Comparative Example 4
[0102] A reference silicon nitride film was prepared according to the method of Example 1, except that lysine was used in place of the complex of aluminum chloride and lysine in step S2, and the other conditions were the same as those of Example 1. Thus, a silicon nitride film with a thickness of Reference silicon nitride film.
[0103] Test Case
[0104] The silicon nitride films prepared in the above examples and comparative examples were tested for dielectric constant, density, adhesion, thickness, and element content (metal, C, N) according to the following methods. The results are shown in Table 1.
[0105] (1) Dielectric constant test: The test method is the resonant cavity method. The substrate with the silicon nitride film deposited is cut into 80 mm × 80 mm squares, and the dielectric constant is measured using a dielectric constant tester at a frequency of 0.6 GHz.
[0106] (2) Density test: The density of the film was tested using an X-ray reflectometer (XRR, model: Malvern Panalytical X'PertPRO).
[0107] (3) Adhesion test: The adhesion between the film and the substrate was tested using the CSI-110 100-grid cross scratch tester in accordance with the DIN EN ISO 2409 (Paint-Coating Grid Cutting Test) method. The adhesion level was divided according to the total area of detachment at the edge and intersection of the cut lines, and the results were determined using the following criteria:
[0108] 0-The cut edges are completely smooth, and there is no peeling at the edges and intersections of the grid;
[0109] 1B-There is a small flake at the intersection of the cuts, and the actual damage in the cross-cut area does not exceed 5%;
[0110] 2B-Small pieces peel off at the edges and intersections of the cuts, and the actual damage in the cross-cut area is 5% (excluding the endpoint value) to 15%;
[0111] 3B-There is flaking at the edge and intersection of the cut, and the actual damage in the cross-cut area is 15% (excluding the endpoint value) to 35%;
[0112] 4B-There is large peeling at the edge and intersection of the cut, and the actual damage in the cross-cut area is 35% (excluding the endpoint value) to 65%;
[0113] 5B - Some squares are partially or completely peeled off, and the actual damage in the cross-cut area is greater than 65%.
[0114] (4) Thickness test: The thickness of the silicon nitride film was tested using a transmission electron microscope (TEM, model Talos F200X).
[0115] (5) Element content test: The element composition and content of the film were tested using an XPS tester (ThermoFisher EscaLab Xi+).
[0116] (6) Resistance test: The resistance of the film was tested using a HTIM-300 high temperature resistance insulation tester.
[0117] Table 1
[0118]
[0119] It can be seen from the results in Table 1 that, compared with Comparative Examples 1 to 4, the silicon nitride films provided by Examples 1 to 5 have a lower dielectric constant, a higher density and a higher adhesion to the substrate, and the film quality is high. Although a certain amount of metal is introduced, the silicon nitride film has a larger resistance as a whole, can meet the electrical insulation requirements, and has good application prospects.
[0120] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary 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 intent of the present invention.
Claims
1. A method for preparing a silicon nitride thin film, characterized in that: The preparation method comprises: S1. placing a substrate in a reaction chamber, introducing an aminosilane precursor into the reaction chamber by atomic layer deposition and chemically adsorbing the precursor on the substrate to obtain a first reaction product; S2. introducing a metal inorganic salt and an amino acid complex into a reaction chamber by atomic layer deposition and performing a first reaction with the first reaction product to obtain a second reaction product; S3. introducing a nitrogen source plasma gas into the reaction chamber to perform a second reaction with the second reaction product to obtain a carbon-metal co-doped silicon nitride layer; S4. After repeating steps S1 to S3 at least twice, a carbon-metal co-doped silicon nitride film is obtained.
2. The method for preparing a silicon nitride thin film according to claim 1, characterized in that: The aminosilane precursor comprises at least one of the compounds represented by formula (1) to (4), In formulas (1) to (4), R1 to R 20 Each is independently a hydrogen atom or a C1-C5 alkyl group.
3. The method for preparing a silicon nitride thin film according to claim 1, characterized in that: In step S1, the method of introducing an aminosilane precursor into a reaction chamber by atomic layer deposition and chemically adsorbing the aminosilane precursor onto a substrate comprises: using gas I as a carrier gas in a pulsed form to introduce the aminosilane precursor into the reaction chamber to contact the aminosilane precursor onto a substrate for chemical adsorption to obtain a first reaction product; Preferably, the gas I is selected from at least one of nitrogen, argon, helium and krypton; Preferably, the flow rate of the gas I is 100 to 400 sccm; Preferably, the aminosilane precursor is in contact with the substrate for chemical adsorption for 3 to 15 seconds.
4. The method for preparing a silicon nitride thin film according to claim 1, characterized in that: In step S2, the method of introducing the metal inorganic salt and amino acid complex into the reaction chamber by atomic layer deposition and performing a first reaction with the first reaction product comprises: using gas II in the form of pulses to introduce the metal inorganic salt and amino acid complex into the reaction chamber to contact with the first reaction product to perform a first reaction, thereby obtaining a second reaction product; Preferably, the gas II is selected from at least one of nitrogen, argon, helium and krypton; Preferably, the flow rate of gas II is 100 to 400 sccm; Preferably, the time for the first reaction of the complex of the metal inorganic salt and the amino acid in contact with the first reaction product is 3 to 15 seconds.
5. The method for preparing a silicon nitride thin film according to claim 1, characterized in that: The metal inorganic salt is selected from at least one of aluminum chloride, gallium chloride, indium chloride and thallium chloride; Preferably, the amino acid is at least one selected from alanine, aspartic acid, isoleucine, leucine, lysine, glutamic acid and glutamine.
6. The method for preparing a silicon nitride thin film according to claim 1, characterized in that: In step S3, the nitrogen source plasma gas is nitrogen plasma gas and / or ammonia plasma; Preferably, the flow rate of the nitrogen source plasma gas is 100 to 400 sccm; Preferably, the time for the second reaction between the nitrogen source plasma gas and the second reaction product is 20 to 60 seconds.
7. The method for preparing a silicon nitride thin film according to claim 1, characterized in that: In steps S1 to S3, the temperature of the reaction chamber is independently 200 to 500°C, and the pressure is 150 to 500Pa.
8. A silicon nitride film prepared by the method according to any one of claims 1 to 7.
9. The silicon nitride thin film according to claim 8, characterized in that: The thickness of the silicon nitride film is 10. Use of the silicon nitride film according to claim 8 or 9 in the field of semiconductor materials and / or microelectronics.