Method for synthesizing tetramethylsilane

Abstract

A synthesis method for tetramethylsilane (4MS) is disclosed, comprising the step of reacting Si(CH3)xCl4-x (where x is an integer from 0 to 3) with trimethylaluminum (TMA).

Description

Technology Field

[0001] The present disclosure relates to a novel method for synthesizing tetramethylsilane. Specifically, a method for synthesizing tetramethylsilane using trimethylaluminum (TMA) is disclosed. Background Technology

[0002] In the semiconductor back-end of line (BEOL) process, resistance-capacitance delay (RC delay) occurs, which degrades the response speed of a device due to the line resistance of metal wiring and the dielectric constant of the interlayer insulating layer surrounding the metal wiring. To resolve this RC delay, the Damascene process was developed, which replaces the metal wiring with copper and the interlayer insulating layer with a material having a low dielectric constant. The Damascene process includes a step of planarizing the copper metal wire through Chemical-Mechanical Polishing (CMP) after wire formation, and a step of depositing a SiCN / SiOC layer on the wiring layer. The deposited SiCN / SiOC layer functions to prevent etching gases (particularly dry etching gases) or moisture (H2O) from penetrating the interlayer insulating layer and is used as an etch stop layer (ESL).

[0003] Meanwhile, as the size of semiconductor devices becomes increasingly smaller, there is a demand for thinner ESLs. Among ESL materials, tetramethylsilane (4MS) is attracting attention because it can produce thin ESL films with a low dielectric constant (k) of about 2.8 and can recover the insulating layer damaged during the polishing (etching) process.

[0004] A method for synthesizing tetramethylsilane is known as the method of the following reaction scheme disclosed by Sundermeyer, W. et al.:

[0005] [Reaction Equation 1]

[0006]

[0007] However, conventional synthesis methods are not suitable for commercial use because the reaction temperature is very high and gaseous Cl2 is formed as a byproduct.

[0008] Against this backdrop, the inventors have completed the present disclosure as a result of diligent research efforts to develop a novel synthesis method of tetramethylsilane that can be used in large-scale processes. Prior art literature

[0009] Sundermeyer, W., & Verbeek, W. (1966). A Method for the Preparation of Methylmetal Compounds. Angewandte Chemie International Edition in English, 5(1), 1-6. The problem to be solved

[0010] The purpose of the present disclosure is to develop a novel synthesis method for tetramethylsilane that can be used in large-scale processes. means of solving the problem

[0011] As one embodiment for achieving the above objective, a synthesis method is disclosed as a method for synthesizing tetramethylsilane, comprising the step of reacting a compound of the following formula (I) with trimethylaluminum (TMA):

[0012] [Chemical Formula (I)]

[0013] Si(CH3) x Cl 4-x ; In this case, x is an integer from 0 to 3.

[0015] Hereinafter, a novel method for synthesizing tetramethylsilane according to the present disclosure will be described in detail. Brief explanation of the drawing

[0016] Figure 1 is the NMR result of tetramethylsilane synthesized according to the present disclosure before purification. Figure 2 is the NMR result after purification of tetramethylsilane synthesized according to the present disclosure. Figure 3 is the result of GC analysis of tetramethylsilane synthesized according to the present disclosure. Specific details for implementing the invention

[0017] Hereinafter, embodiments are described in detail with reference to the attached drawings. However, various modifications may be made to the embodiments, and thus the scope of the patent application is not limited or restricted by these embodiments. It should be understood that all modifications, equivalents, and substitutions to the embodiments are included within the scope of the rights.

[0018] The terms used in the embodiments are for illustrative purposes only and should not be interpreted as intended to be limiting. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0019] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the embodiments pertain. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0020] The term “about” is understood to refer to a range of numbers that a person skilled in the art would consider equivalent to the stated value in terms of achieving the same function or result.

[0021] All numerical ranges presented throughout this specification include their upper and lower values, and all narrower numerical ranges falling within said ranges, and all such narrower numerical ranges are deemed to be clearly and specifically described herein.

[0022] “In this specification, even if there is no explicit indication of singular or plural for a noun, such as ‘one,’ ‘one,’ or ‘~s,’ the noun always means ‘at least one’ or ‘one or more’ and includes the plural form of the noun.”

[0023] Components included in any one embodiment and components having common functions shall be described using the same names in other embodiments. Unless otherwise stated, the descriptions given in any one embodiment may also apply to other embodiments, and specific descriptions shall be omitted to the extent of overlap.

[0024] Throughout this specification, "%" used to indicate the concentration of a particular substance is (weight / weight) % for solid / solid, (weight / volume) % for solid / liquid, and (volume / volume) % for liquid / liquid, unless otherwise noted.

[0026] Throughout this specification, the term “high purity” means that the purity of the material is at least 95%, or at least 98%, or at least 99%, or at least 99.5%, or at least 99.9%.

[0028] The present disclosure relates to a novel method for synthesizing tetramethylsilane. In particular, a method for synthesizing high-purity tetramethylsilane is disclosed.

[0030] In one aspect of the present disclosure, a synthesis method is disclosed comprising the step of reacting a compound of the following formula (I) with trimethylaluminum (TMA):

[0031] [Chemical Formula (I)]

[0032] Si(CH3) x Cl 4-x ; In this case, x is an integer from 0 to 3.

[0034] In one embodiment, the synthesis method further includes the step of purifying the generated 4MS.

[0036] In one embodiment, the step of reacting the compound of formula (I) with trimethylaluminum is carried out at a temperature of 30 to 50°C. Preferably, the step of reacting the compound of formula (I) with trimethylaluminum is carried out at a temperature of 40°C.

[0038] In one embodiment, the step of reacting the compound of formula (I) with trimethylaluminum includes the step of adding the compound of formula (I) to trimethylaluminum. Since the boiling point of the product is low, the compound of formula (I) is added after cooling as necessary to prevent pressurization of the reactor. At this time, the compound of formula (I) can be cooled to -15 to 0°C.

[0040] In one embodiment, the step of reacting the compound of formula (I) with trimethylaluminum is carried out for 3 to 5 hours. Preferably, the step of reacting the compound of formula (I) with trimethylaluminum is carried out for 4 hours.

[0042] In one embodiment, x is 0, 1, 2, or 3. Preferably, x is 3. It is preferable to use Si(CH3)3Cl because Si(CH3)3Cl is more reactive than Si(CH3)2Cl2 or Si(CH3)Cl3.

[0044] In one embodiment, the synthesis method of 4MS is carried out under conditions without a catalyst. In one embodiment, the synthesis method of 4MS is carried out under conditions without a solvent.

[0046] In one embodiment, Si(CH3) x Cl 4-xThe molar ratio of and TMA is 1:1 to 1:5. In one embodiment where x is 3, the molar ratio of Si(CH3)3Cl to TMA is 1:1 to 1:1.2. Preferably, in one embodiment where x is 3, the molar ratio of Si(CH3)3Cl to TMA is 1:1.1. Similarly, in an embodiment where x is 2, the molar ratio of Si(CH3)2Cl2 to TMA is 1:2 to 1:2.4, preferably 1:2 to 1:2.2, and more preferably 1:2.2. Similarly, in an embodiment where x is 1, the molar ratio of Si(CH3)Cl3 to TMA is 1:3 to 1:3.6, preferably 1:3 to 1:3.5, and more preferably 1:3.3. Si(CH3) x Cl 4-x Since purification is difficult if this remains, a larger amount of TMA is added or the reaction time is extended to Si(CH3) x Cl 4-x Ensure that all reactions occur.

[0048] In one embodiment, the 4MS synthesis method includes dimethylaluminum chloride (DMAC) as a byproduct. In one embodiment including DMAC as a byproduct, the 4MS synthesis method further includes the step of converting DMAC into TMA for reuse. In this case, the method of converting DMAC into TMA may use techniques known in the art, such as the technique disclosed in Korean Patent Publication No. 10-2023-0133905.

[0050] In one embodiment further comprising a step of purifying the generated 4MS, the purification step includes a primary purification step by heating the generated 4MS to 70 to 90°C. The purification step may be performed through reflux. Purification is possible at a temperature that is not relatively high, as the boiling point of 4MS is 26 to 28°C.

[0052] In one embodiment, the purity of the generated 4MS is at least 99.5%. Preferably, the purity of the generated 4MS is at least 99.6%.

[0054] In the synthesis method according to the present disclosure, Si(CH3) x Cl 4-x The step of reacting the compound with TMA and the step of purifying the resulting 4MS can be performed simultaneously. For example, carried out in a reactor connected to a reflux tube, Si(CH3) x Cl 4-x It is possible to selectively capture only 4MS of the product through a reflux column while simultaneously carrying out the reaction between the compound and TMA.

[0056] In one embodiment, the purification step further includes a step of secondary purification by heating the primary purified 4MS to 30 to 50°C.

[0058] In one embodiment of the present disclosure, a method for synthesizing tetramethylsilane (4MS) is provided, comprising the step of reacting Si(CH3)3Cl with trimethylaluminum (TMA) at a temperature of 30 to 50°C; and the step of purifying the resulting 4MS, wherein the molar ratio of Si(CH3)3Cl to TMA is 1:1 to 1:1.2.

[0060] The present disclosure relates to a method for synthesizing tetramethylsilane through a methylation reaction. To add methyl groups to the reactants, methyl lithium and Grignard reagents are primarily used. Grignard reagents include methyl magnesium chloride (MMC) and methyl magnesium bromide (MMB). When methyl lithium and MMC are used as reactants, a synthesis solvent (ether, THF, etc.) is required, and LiCl and MgCl2 salts are formed as byproducts after the reaction. Since additional processes are required to remove the used solvent and the generated salts, there is a disadvantage in that productivity is reduced during large-scale synthesis. Furthermore, in the case of diethyl ether, which is mainly used as a solvent in reactions using methyl lithium, the boiling point is 34°C, which is almost the same as the boiling point of tetramethylsilane (26–28°C), making it difficult to purify the product; thus, there are limitations to its use in the synthesis of tetramethylsilane. When using methyl magnesium chloride, productivity is reduced because a large amount of solvent is required for smooth stirring due to the MgCl2 salt produced.

[0062] In contrast, the synthesis method of the present disclosure using TMA does not require a solvent. Since all reactants of the present disclosure are liquids, the reaction is very simple and advantageous for large-scale synthesis. Furthermore, since all products are liquids, they are advantageous for purification, and because no salts are formed as byproducts, no separate post-processing is required.

[0064] Furthermore, in one embodiment of the present disclosure, only dimethylaluminum chloride (DMAC) is included as a byproduct of the reaction. The boiling point of DMAC is 127°C, which is significantly different from the product 4MS, making it very advantageous for product purification.

[0066] In addition, since DMAC can be recycled into TMA, it can be reused in the present disclosure. That is, the present disclosure is an environmentally friendly 4MS synthesis method in that substantially no waste is generated.

[0068] According to one embodiment of the present disclosure, the synthesis of tetramethylsilane does not require a catalyst, and the reaction of the reactants is completed in 3 to 5 hours under conditions of 30 to 50°C. The present disclosure, which proceeds rapidly at low temperatures without a catalyst, provides a significant advantage in large-scale tetramethylsilane synthesis.

[0070] In addition, the reaction of the present disclosure has a reaction conversion rate of at least 95%, at least 98%, preferably 100%. The reaction of the present disclosure has a yield of 90% to 99%, or a yield of 95% to 99%, or a yield of 98% to 99%.

[0072] Example 1 - Synthesis (Laboratory Scale) and Purification of 4MS

[0074] 7.3 g of TMA (Aldrich) was added to a 25 mL flask purged with nitrogen (N2) and vacuum via a Schlenk line. A reflux apparatus (DURAN) was placed in the flask. ® A coil condenser (Dimroth type) was connected, and the reflux apparatus was set to -5°C to -10°C. 10.0 g of TMSCl (trimethylsilyl chloride) (Aldrich) was slowly added to the flask containing TMA at room temperature. The reflux reaction was carried out at 40°C for 4 hours while stirring the reaction mixture flask. After the reaction was complete, the resulting 4 MS was cooled to room temperature.

[0076] To purify the 4MS generated thereafter, a purification tube (DURAN) in the flask ®Distilling links with a Liebig condenser and a collection flask were connected. At this time, the connection was made under nitrogen (N2) conditions to prevent air from entering the flask. The purification tube and the collection flask were maintained at -5°C to -10°C. The flask containing the product was heated to 40°C at atmospheric pressure, and purification was carried out by increasing the temperature by 5°C whenever no product was produced, and finally, purification was stopped when the temperature reached 80°C.

[0078] The mass and number of moles of the TMA and TMSCl used, and the 4MS and DMAC produced are shown in Table 1 below.

[0079]

[0081] As shown in Table 1, 1 equivalent of 4 MS was produced. This means that all reactants reacted to form 4 MS, which represents the advantages of the present disclosure in terms of yield and cost.

[0083] Example 2 - Synthesis (Scale-up) and Purification of 4MS

[0085] To confirm the feasibility of mass production of 4MS, the reaction was carried out by scaling up. In the same manner as in Example 1, 109.50 g of TMA was added to a 500 mL flask purged with nitrogen and vacuum via a Schlenk line. Reflux apparatus (DURAN ® A coil condenser (Dimroth type) was connected, and the reflux apparatus was set to -5°C to -10°C. 150.00g of TMSCl was slowly added to the flask containing TMA at room temperature over 2 hours. The reflux reaction was carried out at 40°C for 4 hours while stirring the reaction mixture flask. After the reaction was complete, the resulting 4MS was cooled to room temperature.

[0087] To purify the 4MS generated thereafter, a purification tube (DURAN) in the flask ®Distilling links with a Liebig condenser and a collection flask were connected. At this time, the connection was made under nitrogen (N2) conditions to prevent air from entering the flask. The purification tube and the collection flask were maintained at -5°C to -10°C. The flask containing the product was heated to 40°C at atmospheric pressure, and purification was carried out by increasing the temperature by 5°C whenever no product was produced, and finally, purification was stopped when the temperature reached 80°C.

[0089] The mass and number of moles of the TMA and TMSCl used, and the 4MS and DMAC produced are shown in Table 2 below.

[0090]

[0092] As shown in Table 2, even in scale-up experiments, the reactants reacted completely to synthesize 4MS. This suggests the possibility of large-scale 4MS production.

[0094] Example 3 - NMR analysis of the generated 4MS

[0096] The generated 4MS was analyzed by NMR (nuclear magnetic resonance). The instrument used was a Bruker 400 MHz NMR.

[0098] The NMR results of the 4MS generated through Example 2 before and after purification are shown in Figures 1 and 2, respectively. In the NMR result before purification (Figure 1), peaks of TMSCl, 4MS, DMAC, and TMA can be observed. (4MS: 1 ¹H NMR (400 MHz, benzene-d6): δ 0.00 ppm (s, 12H, Si-CH3); TMSCl: 1 ¹H NMR (400 MHz, benzene-d6): δ 0.21 ppm (s, 9H, Si-CH3); TMA: 1 ¹H NMR (400 MHz, benzene-d6): δ-0.35 ppm (s, 9H, Al-CH3); DMAC: 1 ¹H NMR (400 MHz, benzene-d6): δ -0.35 ppm (s, 6H, Al-CH3))

[0100] In contrast, the NMR results after purification (Fig. 2) showed only the peak corresponding to 4MS ( 1 H NMR (400 MHz, benzene-d6): δ 0.00 ppm (s, 12H, Si-CH3)). Through this, it can be confirmed that TMSCl, DMAC, and TMA are removed during the purification process, resulting in a high-purity 4MS.

[0102] Example 4 - GC Analysis of Generated 4MS

[0104] The generated 4MS was analyzed by gas chromatography (GC). The instrument used was the Agilent 7890 GC.

[0106] The GC analysis results of the 4MS generated and purified through Example 2 are shown in Figure 3. As can be seen from Figure 3, it can be confirmed that the generated 4MS has almost no impurities and has a purity of 99.661%.

[0108] Although the embodiments have been described above with reference to the limited drawings, those skilled in the art can apply various technical modifications and variations based on the above. For example, suitable results may be achieved even if the described techniques are performed in a different order than described, and / or if the components of the described system, structure, device, circuit, etc. are combined or assembled in a form different from described, or replaced or substituted by other components or equivalents.

[0109] Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the claims set forth below.

[0111] The present disclosure provides the following aspects:

[0113] Embodiment 1: A method for synthesizing tetramethylsilane (4MS),

[0114] A synthesis method comprising the step of reacting a compound of the following chemical formula (I) with trimethylaluminum (TMA):

[0115] [Chemical Formula (I)]

[0116] Si(CH3) x Cl 4-x ,

[0117] In this case, x is an integer from 0 to 3.

[0119] Embodiment 2: Embodiment 1, wherein the synthesis method further comprises the step of purifying the generated 4MS.

[0121] Embodiment 3: A synthesis method in which, in any one of the aforementioned embodiments, the step of reacting the compound of formula (I) with trimethylaluminum is performed at a temperature of 30 to 50°C.

[0123] Embodiment 4: A synthesis method in which, in any one of the aforementioned embodiments, the step of reacting the compound of formula (I) with trimethylaluminum is performed for 3 to 5 hours.

[0125] Aspect 5: A synthesis method in which, in any one of the aforementioned aspects, x is 3.

[0127] Aspect 6: A synthesis method in which, in any one of the aforementioned aspects, the synthesis method is performed under conditions without a catalyst.

[0129] Aspect 7: A synthesis method in which, in any one of the aforementioned aspects, the synthesis method is performed under conditions without a solvent.

[0131] Embodiment 8: A synthesis method in which, in any one of the aforementioned embodiments, the molar ratio of the compound of formula (I) to TMA is 1:1 to 1:1.2.

[0133] Embodiment 9: A synthesis method in which, in any one of the aforementioned embodiments, the synthesis method comprises dimethylaluminum chloride (DMAC) as a byproduct.

[0135] Aspect 10: A synthesis method in any one of the aforementioned aspects, wherein the synthesis method further comprises the step of converting the DMAC into TMA and reusing it.

[0137] Embodiment 11: A synthesis method in which, in any one of the aforementioned embodiments, the purification step comprises a step of first purifying by heating the generated 4MS to 70 to 90°C.

[0139] Embodiment 12: A synthesis method in which, in any one of the aforementioned embodiments, the purity of the generated 4MS is at least 99.5%.

[0141] A synthesis method, wherein in any one of the aforementioned embodiments, the purification step further comprises a step of purifying the 4MS purified by heating it to 30 to 50°C.

[0143] Embodiment 14: A method for synthesizing tetramethylsilane (4MS),

[0144] A step of reacting Si(CH3)3Cl with trimethylaluminum (TMA) at a temperature of 30 to 50°C; and

[0145] Includes a step of purifying the generated 4MS; and

[0146] A synthesis method in which the molar ratio of Si(CH3)3Cl to TMA is 1:1 to 1:1.2.

Claims

Claim 1 A method for synthesizing tetramethylsilane (4MS), comprising the step of reacting a compound of the following chemical formula (I) with trimethylaluminum (TMA), wherein the synthesis method further comprises the step of generating dimethylaluminum chloride (DMAC) as a byproduct and converting the DMAC into TMA for reuse: [Chemical Formula (I)]Si(CH3) x Cl 4-x In the above chemical formula (I), x is an integer from 0 to 3. Claim 2 A synthesis method according to claim 1, wherein the synthesis method further comprises the step of purifying the generated 4MS. Claim 3 A synthesis method according to claim 1, wherein the step of reacting the compound of formula (I) with trimethylaluminum is performed at a temperature of 30 to 50°C. Claim 4 A synthesis method according to claim 1, wherein the step of reacting the compound of formula (I) with trimethylaluminum is performed for 3 to 5 hours. Claim 5 A synthesis method according to claim 1, wherein x is 3. Claim 6 A synthesis method according to claim 1, wherein the synthesis method is performed under conditions without a catalyst. Claim 7 A synthesis method according to claim 1, wherein the synthesis method is performed under conditions without a solvent. Claim 8 A synthesis method according to claim 5, wherein the molar ratio of the compound of formula (I) to TMA is 1:1 to 1:1.

2. Claim 9 A synthesis method according to paragraph 2, wherein the purification step comprises a step of primary purification by heating the generated 4MS to 70 to 90°C. Claim 10 A synthesis method according to claim 9, wherein the purity of the generated 4MS is at least 99.5%. Claim 11 A synthesis method according to claim 9, wherein the purification step further comprises a step of secondary purification by heating the primary purified 4MS to 30 to 50°C. Claim 12 A synthesis method for tetramethylsilane (4MS), comprising the step of reacting Si(CH3)3Cl and trimethylaluminum (TMA) at a temperature of 30 to 50°C; and the step of purifying the generated 4MS; wherein the molar ratio of Si(CH3)3Cl to TMA is 1:1 to 1:1.

2. Claim 13 delete Claim 14 delete

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