Method for preparing diiodosilane

Abstract

A method for preparing diiodosilane, according to one aspect of the present invention, may comprise: a step of injecting an iodine source into a reaction vessel; a step of injecting an inert gas into the reaction vessel and purging same; a first synthesis step of adding a non-coordinating solvent and an ethylene diamine-based catalyst to the reaction vessel, and then stirring same to synthesize a reaction solution; a second synthesis step of maintaining the temperature inside the reaction vessel at a predetermined temperature, injecting dichlorosilane (DCS) into the reaction solution for a predetermined period of time, and then stirring same to increase the yield; a step of filtering out solids from the reaction solution and washing same; and a step of concentrating and reducing the pressure of the reaction filtrate obtained after the washing step, thereby recovering diiodosilane, and can prepare diiodosilane with high yield and / or high purity at low cost.

Description

Method for producing diiodosilane

[0001] The present invention relates to a method for producing diiodosilane, and more particularly, to a method for producing diiodosilane with high yield and / or high purity at low cost.

[0002] Diiodosilane (DIS) is an organosilicon compound with the chemical formula SiH2I2, and is used in various manufacturing processes in the semiconductor industry.

[0003] Diiodosilane is used to deposit various silicon-containing films for semiconductor manufacturing. Diiodosilane is widely used in processes that utilize low-temperature processes (200°C to 210°C) for semiconductor thin films, such as gap-fill nitride, silicon nitride spacer, and sacrificial film processes.

[0004] As such, diiodosilane plays an important role in the semiconductor industry, and much research has been conducted to improve the manufacturing yield and purity of diiodosilane.

[0005] For example, Korean Patent Publication No. 10-2038215 discloses a method for producing diiodosilane by reacting an alkali metal salt such as lithium iodide (LiI) or sodium iodide (NaI) with dichlorosilane (DCS) in a non-coordinating solvent and then purifying the reacted alkali metal salt.

[0006] However, according to this method, only in an example in which lithium iodide (LiI) among alkali metal salts was reacted with dichlorosilane (DCS) in a pentane solvent, a synthetic yield of diiodosilane of 60-70%, a purification yield of 77%, and a total yield of 45-50% were shown, and there is a limitation in that the purity of the purified diiodosilane was 99.7%.

[0007] In addition, when LiI is used as an iodine source, there is a disadvantage in that the yield varies greatly depending on the particle size of LiI, and since lithium (Li) is an expensive element, using LiI as a raw material for manufacturing diiodosilane increases the process cost.

[0008] The technical problem of the present invention is to provide a method for producing diiodosilane with high yield and / or high purity at low cost.

[0009] The present invention provides a method for synthesizing diiodosilane (DIS) with a relatively high yield and purity, using not only expensive lithium iodide (LiI) as an iodine source, but also relatively inexpensive KI and NaI as iodine sources, and using a diamine catalyst in a non-coordinating solvent.

[0010] A method for producing diiodosilane according to one aspect of the present invention may include a step of introducing an iodine source into a reaction vessel; a step of purging the reaction vessel by injecting an inert gas; a first synthesis step of adding a non-coordinating solvent and an ethylenediamine-based catalyst to the reaction vessel and then stirring to synthesize a reaction solution; a second synthesis step of introducing dichlorosilane (DCS) into the reaction solution for a predetermined period of time and stirring while maintaining the internal temperature of the reaction vessel at a constant temperature to increase the yield; a step of filtering and washing a solid in the reaction solution; and a step of concentrating and depressurizing the reaction filtrate that has gone through the washing step to recover diiodosilane.

[0011] In one embodiment, the iodine source may be lithium iodide (LiI), potassium iodide (KI), or sodium iodide (NaI).

[0012] In one embodiment, the inert gas may be one or more selected from the group consisting of nitrogen (N2), carbon dioxide (CO2), and noble gases.

[0013] In one embodiment, the non-coordinating solvent may be one or more selected from the group consisting of methylene chloride and chloroform.

[0014] In one embodiment, the ethylenediamine-based catalyst may be at least one selected from the group consisting of N,N'-tetraethylethylenediamine (TEEA) and tetrabutylammonium iodide.

[0015] In one embodiment, in the second synthesis step, dichlorosilane may be added to the reaction solution for 5 to 15 hours while maintaining the internal temperature of the reaction vessel at 20 to 35°C.

[0016] The purity of diiodosilane manufactured by the manufacturing method according to one aspect of the present invention as described above may be 97% or higher.

[0017] In addition, the method for producing diiodosilane according to an additional aspect of the present invention may further include a step of purifying the recovered diiodosilane; and the purity of the purified diiodosilane may be 99.9% or higher.

[0018] The conventional method for synthesizing diiodosilane had the disadvantage of having a low yield due to the reaction using only a solvent, and high manufacturing cost due to the use of expensive lithium (Li) as an iodine source.

[0019] Unlike conventional technologies, the method for producing diodosilane according to the present invention can use potassium (K) or sodium (Na), which are significantly cheaper than lithium (Li), as an iodine raw material, and thus has the advantage of producing a high-purity product at a low price.

[0020] In addition, it has the advantage of being able to improve the yield by using a catalyst, and being able to produce diodosilane (DIS) with a purity of 99.9% or higher, preferably 99.99% or higher, through a purification process.

[0021] FIG. 1 is a schematic flowchart illustrating a method for manufacturing diiodosilane according to one embodiment of the present invention.

[0022] FIG. 2 is a nuclear magnetic resonance (NMR) graph of diiodosilane raw material (DIS crude) recovered by a method for producing diiodosilane according to one embodiment of the present invention.

[0023] FIG. 3 is a gas chromatographic / mass spectrometric (GC / MS) graph of diiodosilane raw material (DIS crude) recovered by a method for producing diiodosilane according to one embodiment of the present invention.

[0024] FIG. 4 is a nuclear magnetic resonance (NMR) graph of diiodosilane recovered through a purification process of diiodosilane according to an embodiment of the present invention regarding purification of diiodosilane raw material (DIS crude).

[0025] Hereinafter, embodiments of the present invention will be described in more detail with reference to the attached drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. These embodiments are provided solely to ensure complete disclosure of the present invention and to fully inform those skilled in the art of the scope of the invention.

[0026] FIG. 1 is a schematic flowchart illustrating a method for manufacturing diiodosilane according to one embodiment of the present invention.

[0027] A method for producing diiodosilane according to one aspect of the present invention may include a step (S10) of introducing an iodine source into a reaction vessel; a step (S20) of purging the reaction vessel by injecting an inert gas; a first synthesis step (S30) of adding a non-coordinating solvent and an ethylenediamine-based catalyst to the reaction vessel and then stirring to synthesize a reaction solution; a second synthesis step (S40) of introducing dichlorosilane (DCS) into the reaction solution for a predetermined period of time and stirring to increase the yield while maintaining the internal temperature of the reaction vessel at a constant temperature; a step (S50) of filtering and washing a solid in the reaction solution; and a step (S60) of concentrating and depressurizing the reaction filtrate that has gone through the washing step to recover diiodosilane.

[0028] In the step (S10) of introducing an iodine source into the reaction vessel, the iodine source may be lithium iodide (LiI), potassium iodide (KI), or sodium iodide (NaI).

[0029] One of the main technical features of the present invention is that it provides a method for producing diiodosilane with a relatively high yield and high purity at a low cost compared to the prior art by mixing an ethylenediamine-based catalyst with an iodine source together with a non-coordinating solvent in a process for synthesizing a reaction solution for producing diiodosilane (DIS).

[0030] Since the price of potassium (K) or sodium (Na) is significantly cheaper than that of lithium (Li), when diiodosilane is manufactured by adding a catalyst using potassium iodide (KI) or sodium iodide (NaI) as an iodine raw material by the method according to the present invention, the process cost can be significantly reduced.

[0031] Of course, it is also possible to manufacture diiodosilane using lithium iodide (LiI) according to process conditions such as manufacturing yield or other non-process conditions.

[0032] In the step (S20) of purging by injecting an inert gas into the reaction vessel, the inert gas may be at least one selected from the group including nitrogen (N2), carbon dioxide (CO2), and noble gases.

[0033] According to one embodiment of the present invention, in the purge step (S20), purging may be performed using nitrogen gas for 20 to 60 minutes. Alternatively, purging may be performed using nitrogen gas for about 30 minutes.

[0034] The manufacturing yield of diiodosilane can be improved through the above-described purge step (S20).

[0035] In the first synthesis step (S30) of adding a non-coordinating solvent and an ethylenediamine-based catalyst to a reaction vessel and then stirring to synthesize a reaction solution, the non-coordinating solvent may be at least one selected from the group including dichloromethane (Methylene Chloride, MC) and chloroform, and the ethylenediamine-based catalyst may be at least one selected from the group including N,N'-tetraethylethylemedianmine (TEEA) and tetrabutylammonium iodide.

[0036] Here, the structural formula of N,N'-tetraethylethylenediamine is as follows.

[0037] [Structural formula 1]

[0038]

[0039] After the first synthesis step (S30), a second synthesis step (S40) is performed to increase the yield by adding dichlorosilane (DCS) to the reaction solution for a certain period of time and stirring while maintaining the internal temperature of the reaction vessel at a constant temperature. Here, dichlorosilane may be added to the reaction solution for 5 to 15 hours while maintaining the internal temperature of the reaction vessel at 20 to 35°C. Alternatively, dichlorosilane may be added to the reaction solution for about 10 hours while maintaining the internal temperature of the reaction vessel at 25 to 29°C.

[0040] In the second synthesis step (S40), dichlorosilane can be introduced through PFA tubing, and after introduction of dichlorosilane, the mixture can be stirred for 1 to 3 hours while maintaining the same temperature. Alternatively, after introduction of dichlorosilane, the mixture can be stirred for about 2 hours while maintaining the same temperature. Thereafter, the solids in the reaction solution can be filtered through a filter medium. Through this second synthesis step (S40), the yield of diiodosilane raw material (DIS crude) can be increased.

[0041] In the step (S50) of filtering and washing the solid in the reaction solution, the reaction solution can be washed using a washing solution having the same composition as the non-coordinating solvent used in the first synthesis step (S30). That is, if dichloromethane (Methylene Chloride, MC) was used as the non-coordinating solvent in the first synthesis step (S30), the washing solution can also be dichloromethane, and if chloroform was used as the non-coordinating solvent in the first synthesis step (S30), the washing solution can also be chloroform.

[0042] In the step (S60) of concentrating and depressurizing the washed filtrate to recover diiodosilane, the solvent may be concentrated at atmospheric pressure and the pressure may be reduced to recover diiodosilane at 100 torr or less. In one embodiment, the solvent may be concentrated at atmospheric pressure and the pressure may be reduced to recover diiodosilane at 60 torr to 100 torr. Alternatively, the solvent may be concentrated at atmospheric pressure and the pressure may be reduced to recover diiodosilane at about 80 torr.

[0043] Typically, the diodosilane recovered in this manner can be called diodosilane raw material (DIS crude), and it has been experimentally proven that the purity of the diodosilane raw material (DIS crude) manufactured by the manufacturing method according to one aspect of the present invention is 97% or higher, and the details will be described in the examples below.

[0044] In addition, the method for producing diiodosilane according to an additional aspect of the present invention may further include a step (S70) of purifying the recovered diiodosilane; and by controlling process conditions such as temperature, pressure, and / or reflux ratio of the purifier, high-purity diiodosilane can be obtained.

[0045] In one embodiment, the purity of the diiodosilane that has undergone this purification process may be greater than 99.9%.

[0046] In addition, in one embodiment, it was experimentally proven that when the internal pressure of the purifier is controlled to 10 to 80 torr in the purification step (S70), the reflux ratio of the initial forecut is controlled to 1:5 to 1:20 for recovery, the reflux ratio of the main cut is controlled to 1:1.5 to 1:5 for recovery, the internal temperature is maintained at 45 to 60°C, and the vapor temperature is maintained at 45 to 60°C, it is possible to purify diiodosilane having a purity of 99.99% or higher.

[0047] Typically, increasing the reflux ratio during a refining process increases purity, but it also reduces production and increases energy costs. Therefore, by adjusting process conditions such as the reflux ratio, pressure, and temperature as described above, optimal process conditions can be created to recover high-purity diiodosilane without increasing costs.

[0048] Hereinafter, the present invention will be described in detail using examples and other means to aid understanding. However, the examples according to the present invention may be modified in various ways, and the scope of the present invention should not be construed as being limited to the following examples. The examples of the present invention are provided to more fully explain the present invention to those of average skill in the art.

[0049] [Example 1]

[0050] An example using lithium iodide (LiI) as an iodine source and N,N'-tetraethyl ethylenediamine as a catalyst.

[0051] The reaction formula of [Example 1] can be expressed as follows.

[0052] [Reaction Formula 1]

[0053]

[0054] Below, the specific implementation method of [Example 1] is described.

[0055] A 1 L 3-necked flask that had been well dried by flame was purged with 165.66 grams (1.238 M) of LiI for 30 minutes. The purging was stopped and 600 grams (1200 wt% compared to DCS) of methylene chloride (MC) was added. 2.13 grams (0.012 M, 0.025 equivalents compared to DCS) of N,N'-tetraethyl ethylenediamine (N,N'-tetraethyl ethylenediamine) as a catalyst was added. While maintaining the internal temperature of the reactor at 27±2℃, 50 grams (0.495 M) of dichlorosilane (DCS) was added. The reactor was stirred at the same temperature for 2 hours and the solid was filtered. The filtrate was washed with 250 grams of methylene chloride (MC). After the washing was completed, dichloromethane (Methylene Chloride, MC) was concentrated at atmospheric pressure and then reduced to 80 torr to recover 128 grams (yield 91.07%) of diiodosilane crude. The recovered product was identified by performing nuclear magnetic resonance (NMR) and gas chromatographic / mass spectrometric (GC / MS) analysis.

[0056] FIG. 2 is a nuclear magnetic resonance (NMR) graph of diiodosilane raw material (DIS crude) recovered by the method for producing diiodosilane according to [Example 1]. As a result of confirming the purity of the recovered diiodosilane raw material (DIS crude) by measuring 1H NMR after product recovery, it can be confirmed that the purity was 97.71%. The peak seen at 3.42 ppm in FIG. 2 corresponds to the 1H NMR of diiodosilane, the peak seen at 7.13 ppm corresponds to the 1H NMR of chloroform, which is a solvent, and the small peaks formed around the 1H NMR of diiodosilane correspond to the 1H NMR of impurities containing about 2.3% in the DIS crude.

[0057] In addition, FIG. 3 is a gas chromatographic / mass spectrometric (GC / MS) graph of diiodosilane raw material (DIS crude) recovered by the method for producing diiodosilane according to [Example 1], and after product recovery, a diiodosilane compound with a molecular weight of 284 was confirmed through GC / MS.

[0058] [Example 2]

[0059] An example using sodium iodide (NaI) as an iodine source and N,N'-tetraethyl ethylenediamine as a catalyst.

[0060] The reaction formula of [Example 2] can be expressed as follows.

[0061] [Reaction Formula 2]

[0062]

[0063] Below, the specific implementation method of [Example 2] is described.

[0064] Into a 1 L 3-necked flask that had been well dried by flame, 185.51 grams (1.238 M) of NaI was added and purged with nitrogen for 30 minutes. The purging was stopped and 600 grams of dichloromethane (methylene chloride, MC) was added. 2.13 grams of N,N'-tetraethylethylenediamine (N,N'-tetraethyl ethylenediamine) as a catalyst was added and stirred for 30 minutes. While maintaining the internal temperature of the reactor at 27±2℃, 50 grams (0.495 M) of dichlorosilane (DCS) was added over 10 hours. After the addition was completed, the mixture was stirred at the same temperature for 2 hours. The reaction progress was confirmed using nuclear magnetic resonance (NMR), and the solid was filtered. The filtrate was washed with 250 grams of dichloromethane (methylene chloride, MC). After the washing was completed, dichloromethane (Methylene Chloride, MC) was concentrated at atmospheric pressure, and 95 grams (yield 67.6%) of diiodosilane crude (DIS crude) were recovered at 80 torr under reduced pressure. The purity of the recovered diiodosilane crude (DIS crude) was approximately 97% or higher, which was similar to that in [Example 1].

[0065] [Example 3]

[0066] An example using potassium iodide (KI) as an iodine source and tetrabutylammonium iodide as a catalyst.

[0067] 205.45 grams of KI was placed in a 1 L three-necked flask that had been well dried by flame, and purged with nitrogen for 30 minutes. The purging was stopped, and 600 grams of dichloromethane (methylene chloride, MC) was added. 4.57 grams of tetrabutylammonium iodide, a catalyst, was added, and stirring was performed for 30 minutes. While maintaining the internal temperature of the reactor at 27±2℃, 50 grams (0.495 M) of dichlorosilane (DCS) was added over 10 hours. Upon completion of the addition, the mixture was stirred at the same temperature for 2 hours, and the solid was filtered. The filtrate was washed with 250 grams of dichloromethane (methylene chloride, MC). After the washing was completed, dichloromethane (Methylene Chloride, MC) was concentrated at atmospheric pressure, and 68 grams (yield 48.4%) of diiodosilane crude (DIS crude) were recovered at 80 torr under reduced pressure. The purity of the recovered diiodosilane crude (DIS crude) was approximately 97% or higher, which was similar to that in [Example 1].

[0068] [Comparative Example 1]

[0069] Comparative example using potassium iodide (KI) as an iodine source and no catalyst

[0070] 205.45 grams of KI was placed in a 1 L three-necked flask that had been well dried by flame, and purged with nitrogen for 30 minutes. The purging was stopped, 600 grams of dichloromethane (MC) was added, and stirring was performed for 30 minutes. While maintaining the internal temperature of the reactor at 27±2℃, dichlorosilane (DCS) was added for 10 hours. Upon completion of the addition, the mixture was stirred at the same temperature for 2 hours, and the solid was filtered. The filtrate was washed with 250 grams of dichloromethane (MC). Upon completion of the washing, the dichloromethane (MC) was concentrated at atmospheric pressure, and 35 grams of the product (yield 24.9%) was recovered under reduced pressure at 80 torr.

[0071] Through the above examples and comparative examples, it can be seen that when a catalyst is used, the yield of diiodosilane raw material (DIS crude) is improved compared to when a catalyst is not used.

[0072] [Refining Example]

[0073] Example of purification of diiodosilane raw material (DIS crude)

[0074] The diiodosilane raw material (DIS crude) recovered through [Example 1], [Example 2], and [Example 3] was purified through the following process.

[0075] A thermometer and an inlet were installed in a 1000 mL 3-neck round flask, a column with a column length of 50 cm was installed, glass Rasching (3 mm <diameter> X 2 mm <height>) was filled, and a glass tube capable of implementing a reflux ratio was installed. Cooling water at 4-6℃ was flowed through the cooling tube. Drying was performed for 2 hours using nitrogen, 1200 grams of diiodosilane raw material (DIS crude) was introduced, and the reboiler was heated to 65℃. The internal pressure of the purifier was adjusted to 15 torr, and the initial forecut recovered 120 grams by adjusting the reflux ratio to 1:10, and the main cut recovered 900 grams by adjusting the reflux ratio to 1:3. The internal temperature was 49.5 to 50.5℃, and the vapor temperature was maintained at 48.2℃. The purity of diiodosilane recovered through the above purification process was 100%.

[0076] Figure 4 is a nuclear magnetic resonance (NMR) graph of diiodosilane recovered through a purification process of diiodosilane raw material (DIS crude) according to [Purification Example]. The NMR data of the purified product confirms that the purity of diiodosilane is 100%.

[0077] While the present invention has been described above with reference to the accompanying drawings and the preferred embodiments described above, the present invention is not limited thereto, but is defined by the claims set forth below. Accordingly, those skilled in the art will appreciate that various modifications and variations of the present invention can be made without departing from the technical spirit of the claims set forth below.

Claims

1. Step of adding iodine source into the reaction vessel; A step of purging by injecting inert gas into the reaction vessel; A first synthesis step of adding a non-coordinating solvent and an ethylenediamine catalyst to a reaction vessel and then stirring to synthesize a reaction solution; A second synthesis step in which dichlorosilane (DCS) is added to the reaction solution for a certain period of time and stirred while maintaining the internal temperature of the reaction vessel at a constant temperature to increase the yield; A step of filtering and washing the solid in the above reaction solution; and A method for producing diiodosilane, comprising: a step of concentrating and reducing pressure of the reaction filtrate that has undergone the above washing step to recover diiodosilane.

2. In claim 1, A method for producing diiodosilane, wherein the iodine raw material is lithium iodide (LiI), potassium iodide (KI) or sodium iodide (NaI).

3. In claim 1, A method for producing diiodosilane, wherein the above inert gas is at least one selected from the group consisting of nitrogen (N2), carbon dioxide (CO2), and noble gases.

4. In claim 1, A method for producing diiodosilane, wherein the non-coordinating solvent is at least one selected from the group consisting of dichloromethane (methylene chloride, MC) and chloroform.

5. In claim 1, A method for producing diiodosilane, wherein the ethylenediamine-based catalyst is at least one selected from the group consisting of N,N'-tetraethylethylemedianmine (TEEA) and tetrabutylammonium iodide.

6. In claim 1, In the second synthesis step, A method for producing diiodosilane, characterized in that dichlorosilane is added to a reaction solution for 5 to 15 hours while maintaining the internal temperature of the reaction vessel at 20 to 35°C.

7. In claim 1, A step of purifying the recovered diiodosilane is further included; A method for producing diiodosilane, wherein the purified diiodosilane has a purity of 99.9% or higher.

8. A diiodosilane manufactured by the method of claim 1, Diiodosilane with a purity of 97% or more, recovered by concentration and depressurization.

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