Methods for preparing organotin compounds

Abstract

This invention provides a convenient method for preparing certain organotin compounds having alkyl and alkylamino or alkyl and alkoxy substituents. The method provides the organotin compounds in high-purity form, which are particularly suitable as precursors for depositing high-purity tin oxide films in extreme ultraviolet (EUV) lithography techniques, for example, for the manufacture of certain microelectronic devices.

Description

Technical Field

[0001] This invention belongs to the field of organotin chemistry. More specifically, this invention relates to a convenient method for preparing certain organotin compounds. Background Technology

[0002] Certain organotin compounds have been shown to be suitable for depositing high-purity tin oxide films in applications such as extreme ultraviolet (EUV) lithography used in the manufacture of certain microelectronic devices.

[0003] Organotin compounds having combinations of alkylamino and alkyl groups have attracted considerable attention. Therefore, there is a need for improved methods for manufacturing such organotin compounds in high-purity form for depositing high-purity tin oxide films. Summary of the Invention

[0004] A convenient method is provided for preparing certain organotin compounds having alkyl and alkylamino substituents or alkyl and alkoxy substituents. In one embodiment, the method provides an organotin precursor compound, such as tris(dimethylamino)isopropyltin (CAS No. 1913978-89-8), in high-purity form. Therefore, the product of the method is particularly suitable for depositing high-purity tin oxide films in extreme ultraviolet (EUV) lithography techniques, for example, for the fabrication of microelectronic devices.

[0005] This invention relates to a method for preparing compounds of formula (I):

[0006]

[0007] Each R is independently selected from C1-C5 alkyl groups, and each R 1 Independently selected from C1-C5 alkyl groups, and R 2 Selected from hydrogen or C1-C5 alkyl groups. The method comprises using a compound of formula (A).

[0008]

[0009] Where M is selected from sodium, lithium, or potassium, and is consistent with formula LR 2 Compound contact, where L is a dissociative group.

[0010] The present invention further relates to a method for preparing a compound of formula (I):

[0011]

[0012] Each R is independently selected from C1-C5 alkyl groups, and each R 1 Independently selected from C1-C5 alkyl groups, and R 2 Selected from hydrogen or C1-C5 alkyl groups. The method comprises using a compound of formula (II):

[0013]

[0014] Each R 3 Independently selected from straight-chain or branched C1-C8 alkyl, phenyl, and substituted phenyl groups, and related to formula (R 4 )3Si-N(R)(R 1 Compound contact.

[0015] This invention further relates to compounds of formula (II):

[0016]

[0017] Each R 3 Independently selected from straight-chain or branched C1-C8 alkyl, phenyl, and substituted phenyl groups, and R 2 Selected from hydrogen or C1-C5 alkyl. Detailed Implementation

[0018] As used in this specification and the appended claims, unless the context clearly specifies otherwise, the singular forms “a / an” and “the” include a plural of indicators. As used in this specification and the appended claims, unless otherwise clearly specified herein, the term “or” is generally used to mean “and / or”.

[0019] The term "approximately" generally refers to a range of numerical values ​​that are considered equivalent to the stated value (e.g., having the same function or result). In many cases, the term "approximately" may include numerical values ​​rounded to the nearest significant number.

[0020] The range of values ​​expressed using endpoints includes all values ​​contained within the range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0021] In a first aspect, the present invention provides a method for preparing a compound of formula (I):

[0022]

[0023] Each R is independently selected from C1-C5 alkyl groups, and each R 1 Independently selected from C1-C5 alkyl groups, and R 2 Selected from hydrogen or C1-C5 alkyl. The method comprises using a compound of formula (A)

[0024]

[0025] With LR 2A combination of compounds, wherein L is a deactivating group, such as a halide or a substituted or unsubstituted aromatic or sulfonic acid alkyl ester, and M is selected from sodium, lithium, or potassium. For example, a compound of formula (A) can be combined with a compound of formula LR. 2 The compounds are in contact, where L is bromine, iodine, or chlorine. As a specific example, L is iodine.

[0026] In the above method, each R and each R 1 It may be independently selected from straight-chain or branched-chain alkyl groups, including methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, sec-butyl, n-pentyl, isopentyl, or sec-pentyl. In a particular embodiment, each R and each R 1 Independently selected from C1-C3 alkyl groups, such as methyl, ethyl, or propyl. Furthermore, in the above method, R... 2 Selected from C1-C5 alkyl groups, which may be substituted or unsubstituted straight-chain or branched alkyl groups. For example, R 2 It can be a straight-chain or branched alkyl group, including methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, sec-butyl, n-pentyl, isopentyl, or sec-pentyl. Additionally, R... 2 It can be a cyclic C1-C5 group, such as cyclopropyl. Furthermore, R... 2 These can be unsaturated C1-C5 groups, such as vinyl or ethynyl groups. 2 Any of the groups can be further substituted, for example, by one or more halogen groups or ether groups. For example, R 2 It can be a compound with the formula –(CH2). n (CH a F b ) m Fluorinated alkyl groups, wherein m is 1 to 5 and m+n is 1 to 5, and wherein b is 1 to 3 and a+b = 3, include monofluorinated C1-C5 alkyl groups, such as -CH2F or -CH2CH2F groups; and perfluorinated C1-C5 groups, such as -CF3 or CF2CF3 groups. Alternatively, R 2 It may be an alkyl ether group, wherein the alkyl portion is C1-C5 alkyl. In a particular embodiment, each R and each R 1 It is methyl and R 2 M is methyl, ethyl, or isopropyl. Furthermore, M may preferably be lithium. Compound (A) is a useful intermediate for synthesizing compound (I).

[0027] Compound of formula (A):

[0028]

[0029] It can be prepared by reacting a dihalostane, such as SnCl2, with a compound of formula (B):

[0030]

[0031] In this regard, at least about 3 molar equivalents of compound (B) are used to form compound (A) based on the amount of SnCl2, but additional equivalents may be used as needed. For example, at least about 3.1 molar equivalents may be used, including at least about 3.25, 3.5, or 3.75 to about 4 molar equivalents of compound (B). Examples of compounds (B) include non-nucleophilic strong bases, such as lithium dimethylamino, lithium methylethylamino, lithium diethylamino, etc. The reaction can generally be carried out at a moderately high temperature ranging from about -15°C to, for example, about 60°C, but other temperatures may be used depending on, for example, the scale of the reaction or the reaction time. For example, the reaction temperature may be between about -30°C and about 90°C, including about -10°C to about 80°C and about -5°C to about 70°C. In some embodiments, a reaction temperature above 0°C may be preferred. Suitable solvents include aprotic solvents, such as alkanes like hexane and aromatic solvents like toluene, as well as polar aprotic solvents, such as dimethoxyethylene and tetrahydrofuran. Other suitable solvents will be known or can be determined by those skilled in the art. Additionally, one or more of the steps in this method may preferably be carried out under conditions that minimize the exposure of the material and / or product to light (e.g., using amber glassware).

[0032] Therefore, once compound (A) has been formed in situ, it can be combined with compound LR. 2 Compound reaction, where R 2 And L, as defined above, to provide a compound of formula (I). In one embodiment, the compound of formula (I) has a specific structure:

[0033]

[0034] In a second aspect, the present invention provides a method for preparing a compound of formula (I):

[0035]

[0036] Where each R and R 1 As described above. In this respect, the method comprises using a compound of formula (II):

[0037]

[0038] Each R 3 Independently selected from straight-chain or branched C1-C8 alkyl, phenyl, and substituted phenyl groups, and related to formula (R 4 )3Si-N(R)(R 1 ) compound combination, wherein R 4 Selected from C1-C3 alkyl groups. For example, compounds of formula (II) can be reacted with compounds of formula (R). 4)3Si-N(R)(R 1 ) compound contact, wherein R 4 R is methyl. In one embodiment, for compounds of formula (II), R 2 It is methyl, ethyl, or isopropyl, and each R 3 It is a methyl group.

[0039] In this respect, compared with compound (II), using at least about 3 molar equivalents of compound (R) 4 )3Si-N(R)(R 1 Compounds of formula (I) may be used to form compounds of formula (R), but additional equivalents may be used as needed. In a particular instance, formula (R) 4 )3Si-N(R)(R 1 The compound is (CH3)3SiN(CH3)2.

[0040] Examples of substituted phenyl groups include phenyl groups substituted one or more times with groups selected from: C1-C4 alkyl, C1-C4 alkoxy, C1-C4 alkylsulfonyl, hydroxy, cyano, nitro, halogen, trihalomethyl, phenyl, phenoxy, C3-C6 cycloalkyl, etc. Specific examples of substituted phenyl groups include 2,6-di-tert-butylphenyl-1-yl, 2,4,6-trimethylphenyl, etc.

[0041] On the other hand, the present invention relates to compounds of formula (II) as described above, which have been unexpectedly found to be suitable as intermediates for the synthesis of compounds of formula (I).

[0042] The intermediate of formula (II) can be obtained by reacting a dihalostane, such as SnCl2, with a molar excess of formula M-OR. 3 Prepared by a reaction of compounds, wherein M and R 3 As described above, a compound of formula (C) is provided:

[0043]

[0044] Where n is greater than or equal to 1. This compound can then be made compatible with formula XR. 2 The compound reaction yields compound (II).

[0045] In the above aspects, n is greater than or equal to 1, which depends on R in equation (C). 3 The relative size of the groups, and in some cases, can be extremely large or indeterminate, depending on the polymerization level of the repeating units shown above. Therefore, as demonstrated, compounds of formula (C) will tend to form dimers, trimers, oligomers, and even extremely long linear polymers of indeterminate length. For example, compounds of formula (C) will have the following structure:

[0046]

[0047] Furthermore, the formation of compounds of formula (C) will always produce mixed groups of substances, such as dimers, trimers, etc. The intermediate compounds of formula (C) can be formed by reacting SnCl2 with formula M-OR. 3 Prepared by a reaction of compounds, wherein M and R 3 As defined above. In some cases, a molar excess may be used, for example, approximately 2 molar equivalents of the formula M-OR. 3 The compound can be used, but additional equivalents may be used as needed. For example, at least about 2.1 molar equivalents (including at least about 2.25, 2.5, or 2.75 to about 3 equivalents) of the compound of formula (B) may be used. For the first aspect, the reaction may be carried out at a moderately high temperature ranging from about -15°C to, for example, about 60°C, but other temperatures may also be used. For example, the reaction temperature may be between about -30°C and about 90°C, including about -10°C to about 80°C and about -5°C to about 70°C. In some embodiments, a reaction temperature above 0°C may be preferred. Suitable solvents include aprotic solvents, including alkanes such as hexane and aromatic solvents such as toluene; and polar aprotic solvents, including, for example, dimethoxyethylene and tetrahydrofuran. Other suitable solvents will be known or may be determined by those skilled in the art. In addition, one or more of the steps of this method may preferably be carried out under conditions that minimize light exposure of the materials and / or products (e.g., using amber glassware).

[0048] On the other hand, the present invention provides a method in which, for example, at room temperature, it can be achieved using formula R 3 The method for converting the compound of formula (I) into the compound of formula (II) by alcohol treatment with -OH is shown in the following scheme:

[0049]

[0050] By converting the amide tin of formula (I) to the tin alkoxide of formula (II), any impurities generated by the reaction that forms the amide tin are also converted. For example, the compound of formula (I) may include impurities having formula (Ia):

[0051]

[0052] It is extremely difficult to separate from compound (I) by distillation, to say the exact reason. These impurities are more readily removed from compound (II) when the mixture is converted to the corresponding alkoxide, as shown above. Furthermore, when R... 3 When the group is bulky (e.g., isopropyl), purification by recrystallization is also possible. Once purified, the compound of formula (II) can then be reacted with the compound of formula (R) as discussed above. 4 )3Si-N(R)(R1 The compound reacts to form a compound of formula (I) with a significantly reduced amount, for example, removing more than 90%, 95%, 97%, or 99% of this impurity. Therefore, this aspect can be a method for purifying compound (I).

[0053] As noted above, the resulting compound of formula (I) is suitable as a precursor for depositing tin oxide films onto the surface of microelectronic devices.

[0054] The invention can be further illustrated by the following examples of certain instances thereof, but it should be understood that, unless otherwise specifically indicated, these examples are included for illustrative purposes only and are not intended to limit the scope of the invention.

[0055] Example

[0056] Example 1

[0057] Stannous chloride II (SnCl2) (1.0 g, 5.21 mmol) and lithium dimethylamino (LiN(CH3)2) (0.836 g, 16.4 mmol) were placed in a 20 mL scintillation flask equipped with a magnetic stir bar and diluted with tetrahydrofuran (THF) (10 mL). The resulting pink mixture was heated at 55 °C for 60 hours. The resulting gray mixture was filtered through a 0.2 μm syringe filter to obtain a deep red solution. 2-Iodopropane (0.885 g, 5.21 mmol) was added to the resulting deep red solution and the reaction mixture was heated at 60 °C with stirring for one hour, thereby changing the color to a lighter orange. Regarding the resulting pure reaction mixture... 1 H- and 119 Sn-NMR is consistent with the formation of iPrSn(N(CH3)2)3 (119Sn-NMR, -64.18ppm).

[0058] Example 2 (by R) 2 Sn(NR)(NR 1 Preparation of R 2 Sn(OR 3 )3)

[0059] iPrSn(N(CH3)) 2)3 (1.0 g, 3.4 mmol) was placed in a flask and hexane (3.5 mL) was added. Methanol (0.40 g, 12.5 mmol) was added to the mixture at room temperature and the reaction occurred immediately, as evidenced by bubbling. After 5 minutes, the solvent was removed under reduced pressure to give a white solid (0.76 g, 2.98 mmol, 87.7% yield). 1 H-NMR (400MHz, C6D6, 298K) δ3.81 (s, 9H); 2.38 (m, 1H); 1.48 (d, 6H) ppm.

[0060] Example 3 (by R) 2 Sn(OR 3 )3 Preparation of R 2 Sn(NR)(R 1 ))

[0061] 2.5 g (9.8 mmol) of iPrSn(OCH3)3 was placed in a 40 mL flask equipped with a stir bar and diluted with 10 mL of toluene. In a separate flask, 3.44 g (29.4 mmol) of (CH3)3SiN(CH3)2 was dissolved in 10 mL of toluene. The (CH3)3SiN(CH3)2 solution was added to the iPrSn(OCH3)3 flask, and the resulting white mixture was heated at 70 °C with stirring for 12 hours. After 1 hour, the reaction produced a clear solution.

[0062] The next morning, the reaction produced a slightly turbid colorless solution. The reactants were cooled to room temperature and volatiles were removed under reduced pressure to obtain a slightly turbid colorless liquid (mass: 2.44 g, crude yield: 84.7%).

[0063] The collected material was placed in a 50 mL round-bottom flask equipped with a stir bar. A short-path distillation head was connected to a thermometer and a 10 mL collection flask. The apparatus was placed under a dynamic vacuum of 800 Torr baseline and the pot was heated to 60 °C. After reaching a pot temperature of 58 °C, a colorless liquid was observed in the collection flask (head temperature: 38 °C) at a pressure of 800 Torr. When no liquid was observed in the condenser, the heating mantle was closed. 0.96 g was collected, a yield of 31.4%. The product was collected on a pure sample. 1 H- and 119 Sn-NMR supports the synthesized iPrSn(N(CH3)2)3 and is consistent with previously collected NMR data.

[0064] Example 4

[0065] In a reaction vessel, SnCl2 can be reacted with 2 molar equivalents of Li-OCH3. The resulting compound is [Sn(OCH3)2]. n It can then be separated and reacted with 2-iodopropane to provide tris(methoxy)isopropyltinane. The resulting tris(methoxy)isopropyltinane can then be reacted with 3 molar equivalents of (CH3)3Si-N(CH3)2 to provide isopropyl(tri)dimethylaminotin.

[0066] Example 5 - Synthesis of MeSn(NMe2)3

[0067] LiSn(NMe2)3 (2.0 g, 7.75 mmol) was placed in a 40 mL flask equipped with a magnetic stir bar and dissolved in tetrahydrofuran (10 mL). In a separate flask, iodomethane (1.31 g, 9.29 mmol) was diluted with THF (2 mL) and added to the LiSn(NMe2)3 solution with stirring, resulting in a cloudy and warm-to-the-touch mixture. The resulting mixture was stirred at room temperature for 2 days. Recordings were made on filtered aliquots of the reaction mixture. 1 H-NMR and 119 Sn-NMR.

[0068] 1 H-NMR (400MHz, THF, 298K): δ0.29 (s, 3H); 2.61 (s, 18H) ppm. 119 Sn{1H}-NMR (149MHz, THF, 298K): δ-15.04ppm.

[0069] Example 6 - Synthesis of EtSn(NMe2)3

[0070] LiSn(NMe2)3 (2.0 g, 7.75 mmol) was placed in a 40 mL flask equipped with a magnetic stir bar and dissolved in tetrahydrofuran (15 mL). In a separate flask, iodoethane (1.44 g, 9.29 mmol) was diluted with THF (2 mL) and the solution was cooled to -35 °C. After cooling, the iodoethane solution was added to the LiSn(NMe2)3 solution with stirring, causing the reactants to become warm to the touch. The resulting mixture was stirred at room temperature for 20 minutes, and the reaction mixture was recorded on filtered aliquots of the reaction mixture. 1 H-NMR and 119 Sn-NMR. EtSn(NMe2)3 is observed by NMR:

[0071] 1 H-NMR (400MHz, THF, 298K): δ0.89 (t, 3H); 1.16 (q, 2H); 2.66 (s, 18H) ppm. 119 Sn{1H}-NMR (149MHz, THF, 298K): δ-39.13ppm.

[0072] Example 7 - Synthesis of CF3CH2Sn(OtBu)3

[0073] CF3CH2Sn(NMe2)3 (2 g, 5.98 mmol) was placed in an amber-colored 40 mL flask equipped with a magnetic stir bar and diluted with hexane (3 mL). In a separate flask, tBuOH (1.32 g, 17.9 mmol) was dissolved in hexane (5 mL) and slowly added dropwise to the tin-amide solution over a two-minute period with stirring. Slight bubbling was observed throughout the addition. After complete addition, the resulting solution was stirred at room temperature for 10 minutes and then dried under reduced pressure to obtain a slightly amber-colored solution. The results were recorded on a C6D6 solution. 1 H-、 13 C-、 19 F- and 119 Sn-NMR supports the formation of CF3CH2Sn(OtBu)3. According to NMR, the product purity is >90%.

[0074] 1 H-NMR (400MHz, C6D6, 298K): δ1.31 (s, 27H); 1.76 (q, 2H)ppm. 13 C-NMR (100MHz, C6D6, 298K): 28.49(q), 33.55, 33.69, 74.41ppm. 119 Sn{1H}-NMR (149MHz, C6D6, 298K): δ-228.35(q)ppm. 19 F-NMR (376MHz, C6D6, 298K); δ-51.95(t)ppm.

[0075] The present invention has been described in detail with particular reference to certain embodiments thereof, but it should be understood that variations and modifications may be made within the spirit and scope of the invention.

Claims

1. A method for preparing a compound of formula (I), ， Each R is independently selected from C1-C5 alkyl groups, and each R 1 Independently selected from C1-C5 alkyl groups, and R 2 Selected from vinyl or acetylene groups, wherein the method comprises: Compound (A) ， With LR 2 The compound is in contact with L, which is bromine, iodine, or chlorine, and M is selected from sodium, lithium, or potassium.

2. The method of claim 1, wherein each R and each R 1 It is independently selected from C1-C3 alkyl groups.

3. The method according to claim 1, wherein the compound of formula A is prepared by reacting a dihalostane with a compound of formula (B): 。 4. The method according to claim 3, wherein the dihalostane is SnCl2.

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