KR20240060518A - Purification method and purification system for silicon-based precursors - Google Patents

Abstract

The present invention relates to the field of electronic precursor purification, and in particular to a purification method and purification system for a silicon-based precursor, the method comprising: (S.1) dispersing an adsorbent in an ionic liquid to obtain an adsorption slurry; (S.2) dissolving the industrial silicon-based precursor in the adsorption slurry, allowing the industrial silicon-based precursor to contact the adsorbent, so that the metal ion impurities in the industrial silicon-based precursor are adsorbed by the adsorbent; and (S.3) after completion of adsorption, rectifying the crude silicon-based precursor to remove light and heavy components in the silicon-based precursor and obtain an electronic grade silicon-based precursor. The present invention changes the environment of the silicon-based precursor during the purification process, effectively separating the silicon-based precursor and the metal ion impurities mixed therein, thereby making it advantageous for the adsorption of the metal ion impurities, and at the same time using various means in combination to remove the metal ion impurities. Improves the physical or chemical adsorption effect.

Description

Method and purification system for silicon-based precursors

The present invention relates to the field of electronic precursor purification, and particularly to a purification method and purification system for silicon-based precursors.

Advanced integrated circuit manufacturing technology is promoting the continuous development of new materials. With the reduction of integrated circuit line width and the increase of transistor density, the application of advanced precursor materials in ultra-scale integrated circuit processing has increasingly become the focus of people's attention. Precursor materials are mainly used in the core processes of semiconductor integrated circuit memory and logic chip manufacturing, such as epitaxy, photolithography, chemical vapor deposition (CVD) and atomic layer deposition (ALD), and are converted to integrated circuit silicon through methods such as chemical reaction. A thin film with specific electrical properties is formed on the wafer surface, which is very important for the quality of the thin film. Silicon-based precursor is an important turning point among them, and has been one of the hot issues in research in the field of core materials for advanced integrated circuits in recent years. Its main use is selective epitaxial growth of SiGe thin films, CVD and ALD growth for different purposes. These include silicon nitride, silicon oxide, low dielectric constant and high dielectric constant thin film materials.

As semiconductor technology continues to develop, silicon-based precursor materials have become the core of integrated circuit process development, and technical indicators such as material purity and metal impurity content have a direct impact on chip quality and performance. In advanced IC manufacturing processes, the purity of silicon-based precursor materials must reach 99.99% or higher, and the metal impurity mass fraction must be less than ^1x109 . In order to meet the needs of the development of the current semiconductor industry, the separation, refining and purification of materials are mainly carried out using technologies such as reactive rectification, complex rectification and adsorption rectification.

The patent with application number 202010256194.7 discloses a purification process for octamethylcyclotetrasiloxane, which uses high-purity argon gas as a carrier gas to remove metal impurities in octamethylcyclotetrasiloxane through an adsorption reaction in a slightly boiling state. removing; Performing rectification and purification to separate octamethylcyclotetrasiloxane from the adsorbent and remove organic impurities, water and oxygen to obtain octamethylcyclotetrasiloxane intermediate; and further purifying the octamethylcyclotetrasiloxane intermediate through secondary rectification to obtain pure octamethylcyclotetrasiloxane with a purity of 99.999% or more, which meets the requirements for optical fiber preform cladding deposition.

The patent with application number 202010256194.7 is a purification method for electronic grade octamethylcyclotetrasiloxane, which is purified by rectification. The process includes the following steps: 1) 99% octamethylcyclotetrasiloxane is added to the rectification tower, at a pressure of 0.02~0.03MPa, the top temperature is 90~96℃, and a small amount of residual hexamethylcyclotrisiloxane (abbreviated as D3) is added to the top of the tower. Remove. 2) The octamethylcyclotetrasiloxane from which D3 has been removed flows out from the bottom of the column and enters the dehydration rectification tower reaction kettle, and a special high-efficiency metal complex ligand with a material weight ratio of 0.01 to 0.1% is added and heated to 90 to 100 ° C. After reacting for 1 to 10 hours, the reaction mixture is rectified under reduced pressure to obtain electronic grade octamethylcyclotetrasiloxane.

Silicon-based precursor materials of the prior art contain many metal impurities and have defects that make it difficult to meet the demands of semiconductor industry development. However, the present invention provides a method for purifying silicon-based precursors to overcome the above-mentioned defects.

In order to achieve the purpose of the above-described invention, the present invention is implemented through the following technical solutions.

In a first aspect, the present invention first provides a method for purifying a silicon-based precursor, the purification method comprising:

(S.1) dispersing the adsorbent in an ionic liquid to obtain an adsorption slurry;

(S.2) dissolving the industrial silicon-based precursor in the adsorption slurry, allowing the industrial silicon-based precursor to contact the adsorbent, so that the metal ion impurities in the industrial silicon-based precursor are adsorbed by the adsorbent; and

(S.3) After completion of adsorption, the silicon-based precursor is rectified to remove light components and heavy components in the silicon-based precursor and obtain an electronic grade silicon-based precursor.

Silicon-based precursors in the prior art are generally applied to metal or organometallic catalysts in the synthesis process, for example, to ternary copper catalysts (Cu, Cu ₂ O, Cu ₂ O) and CuCl in the process of synthesizing chlorosilane. Cu powder reduced by is used as a catalyst. It has also been proven that zinc, aluminum, selenium, antimony, phosphorus, manganese, etc. can be used as cocatalysts for the production of chlorosilane by copper catalyst. In addition, silicon powder, which is a more upstream raw material, often contains impurities such as iron, calcium, and lead. These impurities often participate in reactions during the synthesis of silicon-based precursors and are ultimately introduced into finished silicon-based precursor products. Because these metal impurities have a certain volatility, it is difficult to separate them from the silicon-based precursor using general rectification means. Although these metal impurities do not have a significant impact on general organic silicon synthesis and general material applications, for silicon-containing thin films formed by chemical vapor deposition (CVD) and atomic layer deposition (ALD), these impurities affect the electrical properties of silicon-containing thin films. gives a great shock to

In the prior art, in order to remove metal ion impurities in the silicon-based precursor, the adsorption step is generally increased in the purification process. Generally, the adsorption step is to adsorb the metal ion impurities in the silicon-based precursor by physical or chemical methods by an adsorbent. However, in the adsorption process, the impurity metal ions must be brought into contact with the adsorbent to achieve adsorption, thereby improving the adsorption time to remove the impurity metal. There are many cases where the adsorption effect for ions needs to be improved, but since some metal ion impurities are still coated with a silicon-based precursor and difficult to contact with the adsorbent, there is a limit to improving the adsorption effect of general adsorbents for metal ion impurities.

In the present invention, in order to improve the adsorption effect for metal ions in the silicon-based precursor, the applicant intentionally changed the environment in which the silicon-based precursor is located during the purification process, but when the silicon-based precursor was unexpectedly dissolved in an adsorption slurry composed of an ionic liquid and an adsorbent, , it was found that the adsorption effect for metal ions in the silicon-based precursor was greatly improved. The reason for this is as follows. (1) Ionic liquid is a liquid composed entirely of ions and has good dissolution performance for both organic and inorganic substances. The applicant has discovered that, due to the principle of similar compatibility, the solubility of metal ions in ionic liquids is much higher than that of metal ions in silicon-based precursors. (2) Since the present invention serves to purify the silicon-based precursor under solution conditions, it improves the contact area between the silicon-based precursor and the adsorption slurry. Therefore, the present invention innovatively implements the role of extraction of metal ions in the silicon-based precursor through this method, thereby moving the metal impurities originally dissolved in the silicon-based precursor into the ionic liquid, and furthermore, the interaction between the silicon-based precursor and the metal impurity ions. By releasing the role, it is advantageous to the physical or chemical adsorption role of metal ion impurities by the adsorbent in the adsorption slurry, quickly adsorbing metal ion impurities in the silicon-based precursor, and in the subsequent rectification process of the silicon-based precursor, the metal ion impurities are purified. Prevents evaporation and inflow as a precursor.

Additionally, because the ionic liquid has non-volatile characteristics, the ionic liquid does not flow into the rectified ionic liquid during the rectification process of the silicon-based precursor.

Preferably, the ionic liquid is one or more of an imidazole-based ionic liquid, a quaternary ammonium-based ionic liquid, a quaternary phosphonium-based ionic liquid, a pyrrolidine-based ionic liquid, and a piperidine-based ionic liquid. Includes a combination of

Preferably, the cation of the ionic liquid is N-hexylpyridine, N-butylpyridine, N-octylpyridine, N-butyl-N-methylpyrrolidine, 1-butyl-3-methylimidazole, 1- Propyl-3-methylimidazole, 1-ethyl-3-methylimidazole, 1-hexyl-3-methylimidazole, 1-octyl-3-methylimidazole, 1-allyl-3-methyl Midazole, 1-butyl-2,3-dimethylimidazole, 1-butyl-3-methylimidazole, tributylmethylphosphine, tributylethylphosphine, tetrabutylphosphine, tributylhexylphosphine, Tributyloctylphosphine, tributyldecylphosphine, tributyldodecylphosphine, tributyltetradecylphosphine, triphenylethylphosphine, triphenylbutylphosphine, triphenylmethylphosphine, triphenylpropylphosphine, Triphenylpentylphosphine, triphenylacetonephosphine, triphenylbenzylphosphine, triphenyl(3-bromopropyl)phosphine, triphenylbromomethylphosphine, triphenylmethoxyphosphine, triphenyl ethoxycarboxylic It is any one of bornylmethylphosphine, triphenyl((3-bromopropyl)phosphine, triphenylvinylphosphine, and tetraphenylphosphine.

Preferably, the anion of the ionic liquid is BF ₄ -, PF ₆ -, CF ₃ SO ₃ -, (CF ₃ SO ₂ ) ₂ N-, C ₃ F ₇ COO-, C ₄ F ₉ SO ₃ , CF ₃ COO-, (CF ₃ SO ₂ ) ₃ C-, (C ₂ F ₅ SO ₂ ) ₃ C-, (C ₂ F ₅ SO ₂ ) ₂ N-, SbF ₆ -.

Preferably, the ionic liquid is 1-butyl-3-methylimidazole trifluoromethanesulfonate, 1-butyl-3-methylimidazole dicyanamide salt, 1-ethyl-3-methylimidase. Sol trifluoroacetate, 1-ethyl-3-methylimidazole chloroaluminate, 1-ethyl-2,3-dimethylimidazole tetrafluoroborate, 1-hexyl-3-methylimidazole bistrifluor Lomethanesulfonimide salt, 1-allyl-3-methylimidazole bistrifluoromethanesulfonimide salt, 1-ethyl-3-methylimidazole chloride salt, 1-ethyl-3-methylimidazole Bistrifluoromethanesulfonimide salt, 1-butyl-2-methyl-3-hexadecyl imidazole bisulfate, 1-ethyl-3-methylimidazole tetrafluoroborate, 1-ethyl-3- Methylimidazole carbonate, 1-ethyl-3-methylimidazole L-lactate, 1,3-dimethylimidazole hexafluorophosphate, 1-ethyl-3-methylimidazole hexafluorophosphate, 1 -Propyl-3-methylimidazole hexafluorophosphate, 1-butyl-3-methylimidazole hexafluorophosphate, 1-hexyl-3-methylimidazole hexafluorophosphate, 1-octyl-3- Methylimidazole hexafluorophosphate, 1-decyl-3-methylimidazole hexafluorophosphate, 1-tetradecyl-3-methylimidazole hexafluorophosphate, 1-benzyl-3-methylimidazole Hexafluorophosphate, 1-allyl-3-methylimidazole hexafluorophosphate, 1-vinyl-3-ethylimidazole hexafluorophosphate, 1-vinyl-3-butylimidazole hexafluorophosphate, 1-Hexadecyl-2,3-dimethylimidazole hexafluorophosphate, 1-octyl-2,3-dimethylimidazole hexafluorophosphate, 1,3-dimethylimidazole tetrafluoroborate, 1- Butyl-3-methylimidazole tetrafluoroborate, 1-decyl-3-methylimidazole tetrafluoroborate, 1-benzyl-3-methylimidazole tetrafluoroborate, 1-ethyl-2,3 -dimethylimidazole tetrafluoroborate, 1-propyl-2,3-dimethylimidazole tetrafluoroborate, 1-octyl-2,3-dimethylimidazole tetrafluoroborate, 1-octyl-2, Contains 3-dimethylimidazole tetrafluoroborate.

Preferably, the silicon-based precursor includes any one of octamethylcyclotetrasiloxane, trimethylsilane, tetramethylsilane, trimethylsilylamine, tetraethoxysilane, and diethoxymethylsilane.

Preferably, the adsorbent in step (S.1) includes any one of activated carbon, porous alumina, silica gel powder, zeolite, or molecular sieve.

Preferably, in step (S.1) the outer surface of the adsorbent is also coated with a polymer coating;

The polymer coating body includes one layer of nitrogen-doped matrix layer coated on the outer surface of the adsorbent;

The nitrogen-doped matrix layer is externally chemically bonded to the sodium polyacrylate segments.

In a preferred technical solution of the present invention, the outer surface of the adsorbent is also coated with a layer of polymer coating consisting of a nitrogen-doped matrix layer and sodium polyacrylate segments. Here, since doping of the nitrogen element is used in the nitrogen-doped matrix layer, it can be coordinated and complexed with metal ions, and can play a good role in adsorbing metal ions. Sodium polyacrylate segments react with divalent and more than divalent metal ions, causing a crosslinking reaction, and further coat and fix the metal ions, thereby preventing the metal ions from escaping from the adsorption slurry.

Preferably, the method for producing the adsorbent includes:

(1) Coating a layer of resin containing nitrogen atoms on the surface of the adsorbent;

(2) reacting the adsorbent coated with nitrogen atom resin with hydrogen acrylate to graft acrylic acid groups onto the surface of the adsorbent coated with nitrogen atom resin, thereby forming a nitrogen doped matrix layer, that is, an intermediate, on the adsorbent;

(3) The intermediate is copolymerized with sodium acrylate to obtain an adsorbent coated with a polymer coating.

Preferably, the mass ratio of the intermediate and sodium acrylate in step (3) is 1:(0.5-2).

The applicant of the present invention has discovered that the mass ratio of the intermediate and sodium acrylate has a significant effect on the final adsorption and purification effect. If the amount of sodium acrylate added is too large, the sodium polyacrylate will completely coat the adsorbent, reducing the porosity of the final adsorbent. decreases the adsorption effect on metal ions.

Preferably, the contact temperature between the industrial silicon-based precursor and the adsorbent in step (2) is 0 to 20°C.

In the prior art, the adsorption temperature of the silicon-based precursor during the adsorption and purification process is generally achieved under boiling conditions, but under high temperature conditions, the speed of irregular diffusion movement (i.e., Brownian motion) of metal ions increases, preventing the capture of metal ions by the adsorbent. This is disadvantageous, and the present invention selects to adsorb metal ion impurities in the silicon-based precursor under low temperature conditions, which is advantageous in improving the adsorption effect. At the same time, it saves energy consumption during the adsorption process.

In a second aspect, the present invention also provides a purification system for purifying a silicon-based precursor, the purification system comprising at least:

A purification unit including a purification tank containing a substance, a stirring device that serves to agitate the substance inside the purification tank, and a heating device that heats the purification tank;

a rectification unit installed at the upper end of the purification tank to rectify the tantalum silicon-based precursor obtained by evaporation within the chamber;

A collection unit including a collector connected to the conduit of the rectification unit to collect the silicon-based precursor leaked from the rectification unit; and

It includes a pressure control unit communicating with the collector pipe to control the internal pressure of the entire purification system.

Preferably, it further includes a gas supply unit including a gas tank for introducing inert gas into the purification tank, and a pressure control valve for controlling the flow rate of the delivered inert gas flow.

Preferably, one coldwell is sleeved outside the collector.

Therefore, the present invention has the following beneficial effects.

(1) The present invention changes the environment of the silicon-based precursor during the purification process to effectively separate the silicon-based precursor and the metal ion impurities mixed therein, thereby making it advantageous for the adsorption of the metal ion impurities;

(2) The present invention uses various means in combination to improve the physical or chemical adsorption effect for metal ion impurities;

(3) At the same time, the present invention also saves energy consumption in the adsorption process.

Figure 1 is an electron micrograph of adsorbent A.
Figure 2 is a gas phase detection diagram of industrial octamethylcyclotetrasiloxane.
Figure 3 is a mass spectrum of hexamethylcyclotrisiloxane (D3).
Figure 4 is a mass spectrum of octamethylcyclotetrasiloxane (D4).
Figure 5 is a mass spectrum of decamethylcyclopentasiloxane (D5).
Figure 6 is a gas phase detection diagram of electronic grade octamethylcyclotetrasiloxane obtained after purification.
Figure 7 is a structural schematic diagram of a purification system for purifying the silicon-based precursor of the present invention.

Hereinafter, the present invention will be further described in conjunction with the drawings and specific examples of the specification. Those skilled in the art will be able to implement the present invention based on this description. Additionally, the embodiments of the present invention mentioned in the following description are generally only some embodiments and not all embodiments of the present invention. Therefore, based on the embodiments of the present invention, all other embodiments obtained by a person skilled in the art without the need for efforts to create inventive step shall all fall within the protection scope of the present invention.

[Manufacture of adsorbent coated with polymer coating]

Adsorbent A:

(1) 100 g of porous alumina was dispersed in 100 ml of deionized water, then 50 ml of 37% formaldehyde aqueous solution and 0.1 g of hexamethylenetetramine were added to the water, mixed uniformly, and then 30 g of melamine was added again, After stirring uniformly, the temperature was raised to 80°C and reacted for 30 minutes, then filtered and dried to obtain porous alumina coated with melamine formaldehyde resin;

(2) 100 g of porous alumina coated with melamine formaldehyde resin was dispersed in 200 ml of dichloromethane, then 4.5 g (50 mmol) of acryloyl chloride was added dropwise thereto at 0°C, and reacted for 1 hour. After filtration, intermediate (A) was obtained;

(3) In a 500 mL four-necked flask equipped with a stirrer, reflux condensing tube, thermometer, and dropping funnel, a certain amount of deionized water and 10% of the total mass of the intermediate (A) were added, and then 4.5% of the total mass of the intermediate was added. Sodium bisulfite, a chain transfer agent, was added, stirred and dispersed, heated and raised to 65°C, and then monomeric acrylic acid, accounting for 15% of the system mass, and ammonium persulfate, an initiator, accounting for 0.06% of the system mass, were added dropwise. , maintained for 3 hours after completion of dropwise addition, neutralized with an aqueous solution of sodium hydroxide with a mass fraction of 30% until the pH value reached 7 to 7.5, then filtered, washed and dried to obtain adsorbent A, and electron micrographs were obtained. It is shown in Figure 1.

Adsorbent B:

(1) 100 g of silica gel powder was dispersed in 200 ml of deionized water, then 5 g of dopamine was added to the solution, stirred at room temperature for 8 hours, then filtered and dried to obtain silica gel powder coated with polydopamine;

(2) 100 g of polydopamine-coated silica gel powder was dispersed in 200 ml of dichloromethane, then 4.5 g (50 mmol) of acryloyl chloride was added dropwise to it at 0°C, and reacted for 1 hour. By filtration, intermediate (B) was obtained;

(3) A certain amount of deionized water and 10% of the total mass of the intermediate (B) were added to a 500 mL four-necked flask equipped with a stirrer, reflux condensation tube, thermometer, and dropping funnel, and then 4.5% of the total mass was added. Sodium bisulfite, a chain transfer agent, was added, stirred and dispersed, heated and raised to 65°C, and then monomeric acrylic acid, accounting for 15% of the system mass, and ammonium persulfate, an initiator, accounting for 0.06% of the system mass, were added dropwise. , After the dropwise addition was completed, it was maintained for 3 hours, neutralized with an aqueous solution of sodium hydroxide with a mass fraction of 30% until the pH value reached 7 to 7.5, and then filtered, washed, and dried to obtain adsorbent B.

Adsorbent C:

(1) 100 g of porous alumina was dispersed in 100 ml of deionized water, then 20 g of polyvinyl alcohol was added to the water, stirred uniformly, left for 3 hours, filtered and dried, and then coated with polyvinyl alcohol. Porous alumina was obtained;

(2) 100 g of porous alumina coated with polyvinyl alcohol was dispersed in 200 ml of dichloromethane, then 4.5 g (50 mmol) of acryloyl chloride was added dropwise to it at 0°C, and reacted for 1 hour. , filtered to obtain intermediate (C);

(3) A certain amount of deionized water and 10% of the total mass of the intermediate (C) were added to a 500 mL four-necked flask equipped with a stirrer, reflux condensation tube, thermometer, and dropping funnel, and then 4.5% of the total mass was added. Sodium bisulfite, a chain transfer agent, was added, stirred and dispersed, heated and raised to 65°C, and then monomeric acrylic acid, accounting for 15% of the system mass, and ammonium persulfate, an initiator, accounting for 0.06% of the system mass, were added dropwise. , After the dropwise addition was completed, it was maintained for 3 hours, neutralized with an aqueous solution of sodium hydroxide with a mass fraction of 30% until the pH value reached 7 to 7.5, and then filtered, washed, and dried to obtain adsorbent C.

Adsorbent D:

(1) 100 g of porous alumina was dispersed in 100 ml of deionized water, then 50 ml of 37% formaldehyde aqueous solution and 0.1 g of hexamethylenetetramine were added to the water, mixed uniformly, and then 30 g of melamine was added again, After stirring uniformly, the temperature was raised to 80°C and reacted for 30 minutes, then filtered and dried to obtain porous alumina coated with melamine formaldehyde resin;

(2) 100 g of porous alumina coated with melamine formaldehyde resin was dispersed in 200 ml of dichloromethane, then 4.5 g (50 mmol) of acryloyl chloride was added dropwise thereto at 0°C, and reacted for 1 hour. After filtration, intermediate (A) was obtained;

(3) In a 500 mL four-necked flask equipped with a stirrer, reflux condensing tube, thermometer, and dropping funnel, a certain amount of deionized water and 10% of the total mass of the intermediate (A) were added, and then 4.5% of the total mass of the intermediate was added. Sodium bisulfite, a chain transfer agent, was added, stirred and dispersed, heated to 65°C, and then monomeric acrylic acid, which accounts for 25% of the system mass, and ammonium persulfate, an initiator, which accounts for 0.06% of the system mass, were added dropwise. , After the dropwise addition was completed, it was maintained for 3 hours, neutralized with an aqueous solution of sodium hydroxide with a mass fraction of 30% until the pH value reached 7 to 7.5, and then filtered, washed, and dried to obtain adsorbent D.

[Purification system]

As shown in Figure 2, the present invention also discloses a purification system for purifying a silicon-based precursor, the system comprising at least the following steps.

Since the purification unit 100 includes a purification tank 110 containing materials including an industrial silicon-based precursor, an adsorbent, and an ionic liquid, the silicon-based precursor is divided into an adsorbent and an adsorbent dispersed in an ionic liquid medium inside the purification tank 110. By contact, the metal ion impurities in the silicon-based precursor can be dissolved in the ionic liquid and adsorbed and purified by the adsorbent.

In the present invention, in particular, in order to improve the contact effect of the silicon-based precursor contacting the adsorbent, a stirring device 120 that serves to stir the material inside the purification tank 110 is installed in the purification tank 110, and the stirring device 120 ) includes a drive motor 121 installed at the upper end of the purification tank 110 and a transmission rod 122 connected to this and penetrating deep into the purification tank 110, and the transmission rod 122 has a function of stirring the material. When the stirring paddle 123 is installed and the drive motor 121 is operated, the drive motor 121 drives the transmission rod 122 to rotate, so that the stirring paddle 123 serves as a shear for the material, The stirring effect can be increased.

In order to facilitate the role of temperature control of the material inside the purification tank 110, the present invention also installs a heating device 130 around the purification tank 110 to facilitate the role of heating the material inside the purification tank 110. Let's do it.

A set of rectification units 200 are installed at the upper end of the purification tank 110, and the rectification unit 200 includes one rectification column 210 filled with rectification packing 220 therein. .

The collection unit 300 includes a collector 310 connected to the pipe of the rectification unit 200, and one cold well 320 is sleeved on the outside of the collector 310, and liquid nitrogen is inside the cold well 320. A cooling medium such as the like can be injected, and when the silicon-based precursor comes out of the rectification column 210, it is used to receive collection of the spilled silicon-based precursor, and the collection unit 300 is used to receive the low boiling point material obtained by rectification. It further includes one low boiling point collector 330 for.

The pressure control unit 400 is connected to the collector 310 pipe to control the internal pressure of the entire purification system.

The gas supply unit 500 includes a gas tank 510 that introduces an inert gas into the purification tank 110, and a pressure control valve 520 that controls the flow rate of the delivered inert gas flow.

[Purification of octamethylcyclotetrasiloxane (D4)]

[Example 1]

The method for purifying octamethylcyclotetrasiloxane includes the following steps.

(S.1) 10 kg of silica gel powder and 100 kg of ionic liquid (1-ethyl-3-methylimidazole tetrafluoroborate) are added to the purification tank 110, and the stirring device 120 is operated to purify the silica gel. The powder was allowed to completely disperse in the ionic liquid to obtain an adsorption slurry. Operating the gas supply unit 500, introducing nitrogen gas into the adsorption slurry at a rate of 10 L/h to remove air inside the purification tank;

(S.2) After controlling the internal temperature of the purification tank 110 to 20°C, 50 kg of industrial octamethylcyclotetrasiloxane (D4) is added to the purification tank 110, and the octamethylcyclotetrasiloxane is added to the adsorption slurry. It is stirred to dissolve and contact with the adsorbent, and after stirring and adsorption for 3 hours, the metal ion impurities in the technical octamethylcyclotetrasiloxane are adsorbed by the adsorbent;

(S.3) After completion of adsorption, stop the gas supply from the gas supply unit 500, then control the internal pressure of the purification tank 110 to 0.05 MPa through the pressure control unit 400, and perform the programmed temperature increase and heating. Afterwards, the oil temperature of 98°C received at the upper part of the rectification unit 200 is collected, the light components in the industrial octamethylcyclotetrasiloxane are removed, the pressure inside the purification tank 110 is controlled to 0.02 MPa, and then rectified. The oil with a temperature of 113° C. received at the top of the unit 200 was collected to obtain electronic grade octamethylcyclotetrasiloxane, and the high-boiling material was discharged from the bottom of the purification tank 110.

To compare the change in purity of octamethylcyclotetrasiloxane obtained before and after purification, GC-MS detection was performed on technical octamethylcyclotetrasiloxane and electronic grade octamethylcyclotetrasiloxane obtained after purification.

Here, Figure 3 is a gas phase detection spectrum of industrial octamethylcyclotetrasiloxane, of which the peak at 6.209 min is hexamethylcyclotrisiloxane (D3), and its mass spectrum is shown in Figure 4, the peak at 7.550 min. is octamethylcyclotetrasiloxane (D4), the mass spectrum is shown in Figure 5, the peak at 10.401 min is decamethylcyclopentasiloxane (D5), the mass spectrum is shown in Figure 6, the remaining peaks are It is a high boiling point substance.

The gas phase detection spectrum of electronic grade octamethylcyclotetrasiloxane obtained after purification is shown in Figure 7, and it can be seen that only octamethylcyclotetrasiloxane (D4) is contained after purification.

[Example 2]

The method for purifying octamethylcyclotetrasiloxane includes the following steps.

(S.1) 10 kg of adsorbent A and 100 kg of ionic liquid (1-ethyl-3-methylimidazole tetrafluoroborate) are added to the purification tank 110, and the stirring device 120 is operated to produce silica gel. The powder was allowed to completely disperse in the ionic liquid to obtain an adsorption slurry. Operating the gas supply unit 500, introducing nitrogen gas into the adsorption slurry at a rate of 10 L/h to remove air inside the purification tank;

(S.2) After controlling the internal temperature of the purification tank 110 to 20°C, 50 kg of industrial octamethylcyclotetrasiloxane (D4) is added to the purification tank 110, and the octamethylcyclotetrasiloxane is added to the adsorption slurry. It is stirred to dissolve and contact with the adsorbent, and after stirring and adsorption for 3 hours, the metal ion impurities in the technical octamethylcyclotetrasiloxane are adsorbed by the adsorbent;

(S.3) After completion of adsorption, stop the gas supply from the gas supply unit 500, then control the internal pressure of the purification tank 110 to 0.05 MPa through the pressure control unit 400, and perform the programmed temperature increase and heating. Afterwards, the oil with an oil temperature of 98°C received at the upper part of the rectification unit 200 is collected, the light component (D3) in the industrial octamethylcyclotetrasiloxane is removed, and the internal pressure of the purification tank 110 is controlled to 0.02 MPa. Then, the oil having a temperature of 113° C. received at the upper part of the rectification unit 200 was collected to obtain electronic grade octamethylcyclotetrasiloxane, and the high boiling point material was discharged from the bottom of the purification tank 110.

[Example 3]

The method for purifying octamethylcyclotetrasiloxane includes the following steps.

(S.1) 10 kg of adsorbent B and 100 kg of ionic liquid (1-ethyl-3-methylimidazole tetrafluoroborate) are added to the purification tank 110, and the stirring device 120 is operated to produce silica gel. The powder was allowed to completely disperse in the ionic liquid to obtain an adsorption slurry. Operating the gas supply unit 500, introducing nitrogen gas into the adsorption slurry at a rate of 10 L/h to remove air inside the purification tank;

(S.2) After controlling the internal temperature of the purification tank 110 to 20°C, 50 kg of industrial octamethylcyclotetrasiloxane (D4) is added to the purification tank 110, and the octamethylcyclotetrasiloxane is added to the adsorption slurry. It is stirred to dissolve and contact with the adsorbent, and after stirring and adsorption for 3 hours, the metal ion impurities in the technical octamethylcyclotetrasiloxane are adsorbed by the adsorbent;

(S.3) After completion of adsorption, stop the gas supply from the gas supply unit 500, then control the internal pressure of the purification tank 110 to 0.05 MPa through the pressure control unit 400, and perform the programmed temperature increase and heating. Afterwards, the oil with an oil temperature of 98°C received at the upper part of the rectification unit 200 is collected, the light component (D3) in the industrial octamethylcyclotetrasiloxane is removed, and the internal pressure of the purification tank 110 is controlled to 0.02 MPa. Then, the oil having a temperature of 113° C. received at the upper part of the rectification unit 200 was collected to obtain electronic grade octamethylcyclotetrasiloxane, and the high boiling point material was discharged from the bottom of the purification tank 110.

[Example 4]

The method for purifying octamethylcyclotetrasiloxane includes the following steps.

(S.1) 20 kg of adsorbent B and 100 kg of ionic liquid (1-ethyl-3-methylimidazole tetrafluoroborate) are added to the purification tank 110, and the stirring device 120 is operated to dissolve the silica gel. The powder was allowed to completely disperse in the ionic liquid to obtain an adsorption slurry. Operating the gas supply unit 500, introducing nitrogen gas into the adsorption slurry at a rate of 10 L/h to remove air inside the purification tank;

(S.2) After controlling the internal temperature of the purification tank 110 to 20°C, 50 kg of industrial octamethylcyclotetrasiloxane (D4) is added to the purification tank 110, and the octamethylcyclotetrasiloxane is added to the adsorption slurry. It is stirred to dissolve and contact with the adsorbent, and after stirring and adsorption for 3 hours, the metal ion impurities in the technical octamethylcyclotetrasiloxane are adsorbed by the adsorbent;

(S.3) After completion of adsorption, stop the gas supply from the gas supply unit 500, then control the internal pressure of the purification tank 110 to 0.05 MPa through the pressure control unit 400, and perform the programmed temperature increase and heating. Afterwards, the oil with an oil temperature of 98°C received at the upper part of the rectification unit 200 is collected, the light component (D3) in the industrial octamethylcyclotetrasiloxane is removed, and the internal pressure of the purification tank 110 is controlled to 0.02 MPa. Then, the oil having a temperature of 113° C. received at the upper part of the rectification unit 200 was collected to obtain electronic grade octamethylcyclotetrasiloxane, and the high boiling point material was discharged from the bottom of the purification tank 110.

[Comparative Example 1]

The method for purifying octamethylcyclotetrasiloxane includes the following steps.

(S.1) 10 kg of porous alumina coated with melamine formaldehyde resin and 100 kg of ionic liquid (1-ethyl-3-methylimidazole tetrafluoroborate) are added to the purification tank 110 and stirred. (120) was operated to ensure that the silica gel powder was completely dispersed in the ionic liquid, thereby obtaining an adsorption slurry. Operating the gas supply unit 500, introducing nitrogen gas into the adsorption slurry at a rate of 10 L/h to remove air inside the purification tank;

(S.2) After controlling the internal temperature of the purification tank 110 to 20°C, 50 kg of industrial octamethylcyclotetrasiloxane (D4) is added to the purification tank 110, and the octamethylcyclotetrasiloxane is added to the adsorption slurry. It is stirred to dissolve and contact with the adsorbent, and after stirring and adsorption for 3 hours, the metal ion impurities in the technical octamethylcyclotetrasiloxane are adsorbed by the adsorbent;

(S.3) After completion of adsorption, stop the gas supply from the gas supply unit 500, then control the internal pressure of the purification tank 110 to 0.05 MPa through the pressure control unit 400, and perform the programmed temperature increase and heating. Afterwards, the oil with an oil temperature of 98°C received at the upper part of the rectification unit 200 is collected, the light component (D3) in the industrial octamethylcyclotetrasiloxane is removed, and the internal pressure of the purification tank 110 is controlled to 0.02 MPa. Then, the oil having a temperature of 113° C. received at the upper part of the rectification unit 200 was collected to obtain electronic grade octamethylcyclotetrasiloxane, and the high boiling point material was discharged from the bottom of the purification tank 110.

[Comparative Example 2]

The method for purifying octamethylcyclotetrasiloxane includes the following steps.

(S.1) 10 kg of adsorbent C and 100 kg of ionic liquid (1-ethyl-3-methylimidazole tetrafluoroborate) are added to the purification tank 110, and the stirring device 120 is operated to produce silica gel. The powder was allowed to completely disperse in the ionic liquid to obtain an adsorption slurry. Operating the gas supply unit 500, introducing nitrogen gas into the adsorption slurry at a rate of 10 L/h to remove air inside the purification tank;

(S.2) After controlling the internal temperature of the purification tank 110 to 20°C, 50 kg of industrial octamethylcyclotetrasiloxane (D4) is added to the purification tank 110, and the octamethylcyclotetrasiloxane is added to the adsorption slurry. It is stirred to dissolve and contact with the adsorbent, and after stirring and adsorption for 3 hours, the metal ion impurities in the technical octamethylcyclotetrasiloxane are adsorbed by the adsorbent;

(S.3) After completion of adsorption, stop the gas supply from the gas supply unit 500, then control the internal pressure of the purification tank 110 to 0.05 MPa through the pressure control unit 400, and perform the programmed temperature increase and heating. Afterwards, the oil with an oil temperature of 98°C received at the upper part of the rectification unit 200 is collected, the light component (D3) in the industrial octamethylcyclotetrasiloxane is removed, and the internal pressure of the purification tank 110 is controlled to 0.02 MPa. Then, the oil having a temperature of 113° C. received at the upper part of the rectification unit 200 was collected to obtain electronic grade octamethylcyclotetrasiloxane, and the high boiling point material was discharged from the bottom of the purification tank 110.

[Comparative Example 3]

The method for purifying octamethylcyclotetrasiloxane includes the following steps.

(S.1) 10 kg of adsorbent D and 100 kg of ionic liquid (1-ethyl-3-methylimidazole tetrafluoroborate) are added to the purification tank 110, and the stirring device 120 is operated to produce silica gel. The powder was allowed to completely disperse in the ionic liquid to obtain an adsorption slurry. Operating the gas supply unit 500, introducing nitrogen gas into the adsorption slurry at a rate of 10 L/h to remove air inside the purification tank;

(S.2) After controlling the internal temperature of the purification tank 110 to 20°C, 50 kg of industrial octamethylcyclotetrasiloxane (D4) is added to the purification tank 110, and the octamethylcyclotetrasiloxane is added to the adsorption slurry. It is stirred to dissolve and contact with the adsorbent, and after stirring and adsorption for 3 hours, the metal ion impurities in the technical octamethylcyclotetrasiloxane are adsorbed by the adsorbent;

(S.3) After completion of adsorption, stop the gas supply from the gas supply unit 500, then control the internal pressure of the purification tank 110 to 0.05 MPa through the pressure control unit 400, and perform the programmed temperature increase and heating. Afterwards, the oil with an oil temperature of 98°C received at the upper part of the rectification unit 200 is collected, the light component (D3) in the industrial octamethylcyclotetrasiloxane is removed, and the internal pressure of the purification tank 110 is controlled to 0.02 MPa. Then, the oil having a temperature of 113° C. received at the upper part of the rectification unit 200 was collected to obtain electronic grade octamethylcyclotetrasiloxane, and the high boiling point material was discharged from the bottom of the purification tank 110.

[Purification of tetraethoxysilane]

[Example 5]

The method for purifying tetraethoxysilane includes the following steps.

(S.1) 10 kg of adsorbent A and 100 kg of ionic liquid (1, 3-dimethylimidazole tetrafluoroborate) are added to the purification tank 110, and the stirring device 120 is operated to dissolve the silica gel powder. By allowing it to be completely dispersed in the ionic liquid, an adsorption slurry was obtained. Operating the gas supply unit 500, introducing nitrogen gas into the adsorption slurry at a rate of 10 L/h to remove air inside the purification tank;

(S.2) After controlling the internal temperature of the purification tank 110 to 10°C, 50 kg of industrial tetraethoxysilane is put into the purification tank 110, and the tetraethoxysilane is dissolved in the adsorption slurry and comes into contact with the adsorbent. After stirring and adsorption for 5 hours, the metal ion impurities in the technical tetraethoxysilane are adsorbed by the adsorbent;

(S.3) After completion of adsorption, stop the gas supply from the gas supply unit 500, then control the internal pressure of the purification tank 110 to 0.05 MPa through the pressure control unit 400, and perform the programmed temperature increase and heating. Then, the oil with an oil temperature of 93 to 95°C received at the upper part of the rectification unit 200 is collected, the light components in the industrial octamethylcyclotetrasiloxane are removed, and the internal pressure of the purification tank 110 is controlled to 0.02 MPa. , the oil with a temperature of 108-110°C was collected at the upper part of the rectification unit 200, and electronic grade tetraethoxysilane was obtained, and the high boiling point material was discharged from the bottom of the purification tank 110.

[Purification of tetramethylsilane]

[Example 6]

The method for purifying tetramethylsilane includes the following steps.

(S.1) 10 kg of adsorbent A and 100 kg of ionic liquid (1, 3-dimethylimidazole tetrafluoroborate) are added to the purification tank 110, and the stirring device 120 is operated to dissolve the silica gel powder. By allowing it to be completely dispersed in the ionic liquid, an adsorption slurry was obtained. Operating the gas supply unit 500, introducing nitrogen gas into the adsorption slurry at a rate of 10 L/h to remove air inside the purification tank;

(S.2) After controlling the internal temperature of the purification tank 110 to 0°C, 50 kg of industrial tetramethylsilane is added to the purification tank 110, and stirred so that the tetramethylsilane is dissolved in the adsorption slurry and comes into contact with the adsorbent. After stirring and adsorption for 5 hours, the metal ion impurities in the industrial tetramethylsilane are adsorbed by the adsorbent;

(S.3) After completion of adsorption, stop the gas supply from the gas supply unit 500, then control the internal pressure of the purification tank 110 to 1 atmosphere through the pressure control unit 400, and perform the programmed temperature increase and heating. Afterwards, the oil with a temperature of 26 to 28°C received at the upper part of the rectification unit 200 was collected to obtain electronic grade tetramethylsilane, and the high boiling point material was discharged from the bottom of the purification tank 110.

[Purification of trimethylsilane]

[Example 7]

The method for purifying trimethylsilane includes the following steps.

(S.1) 10 kg of adsorbent A and 100 kg of ionic liquid (1, 3-dimethylimidazole tetrafluoroborate) are added to the purification tank 110, and the stirring device 120 is operated to dissolve the silica gel powder. By allowing it to be completely dispersed in the ionic liquid, an adsorption slurry was obtained. Operating the gas supply unit 500, introducing nitrogen gas into the adsorption slurry at a rate of 10 L/h to remove air inside the purification tank;

(S.2) After lowering the internal temperature of the purification tank 110 to -10°C, 50 kg of industrial trimethylsilane is added to the purification tank 110, and stirred so that the trimethylsilane is dissolved in the adsorption slurry and comes into contact with the adsorbent A. After stirring and adsorption for 5 hours, the metal ion impurities in the industrial trimethylsilane are adsorbed by the adsorbent A;

(S.3) After completion of adsorption, stop the gas supply from the gas supply unit 500, then control the internal pressure of the purification tank 110 to 1 atmosphere through the pressure control unit 400, and perform the programmed temperature increase and heating. Afterwards, the 6-7°C oil contained in the upper part of the rectification unit 200 was collected to obtain electronic grade trimethylsilane, and the high-boiling point material was discharged from the bottom of the purification tank 110.

[Performance test results]

Octamethylcyclotetrasiloxane obtained by purification in Examples 1 to 4 and Comparative Examples 1 to 3, tetraethoxysilane obtained in Example 5, tetramethylsilane obtained in Example 6, and trimethyl obtained in Example 7 The metal ion impurity content in silane is shown in Table 1 below.

item Metal ion impurity content copper steel aluminum manganese nickel zinc Crude pentaoctamethylcyclotetrasiloxane 6.3ppm 3.2ppm 2.7ppm 1.6 ppm 1.2ppm 2.1ppm Example 1 3.2ppb 2.5 ppb 1.2ppb 1.8ppb 1.5 ppb 1.6 ppb Example 2 0.9 ppb 0.7 ppb 0.8 ppb 0.6 ppb 0.5 ppb 0.7ppb Example 3 0.6 ppb 0.5 ppb 0.5ppb 0.2 ppb undetectable 0.4 ppb Example 4 0.5ppb 0.3ppb 0.5 ppb 0.1ppb undetectable 0.2ppb Comparative Example 1 3.0 ppb 2.1 ppb 1.1 ppb 1.7ppb 1.4 ppb 1.5ppb Comparative Example 2 2.3 ppb 1.8ppb 1.0 ppb 1.3ppb 1.2ppb 1.2ppb Comparative Example 3 12.8 ppb 9.6ppb 6.5 ppb 7.2ppb 6.8ppb 5.7 ppb Crude Pentatetraethoxysilane 4.6ppm 2.8 ppm 3.1 ppm 1.8ppm 1.5ppm 1.6ppm Example 5 1.1 ppb 0.8ppb 1.0 ppb 0.7ppb 0.6 ppb 0.6 ppb crude tetramethylsilane 5.2ppm 4.5ppm 3.8ppm 2.3ppm 1.8ppm 2.6 ppm Example 6 0.8ppb 0.6 ppb 0.7ppb 0.3 ppb 0.6 ppb 0.5 ppb Crude Trimethylsilane 3.8ppm 3.5ppm 2.9 ppm 1.8ppm 1.5ppm 1.8ppm Example 7 0.9 ppb 0.7 ppb 0.4ppb 0.5 ppb 0.7ppb 0.6 ppb

From the data in the table above, it can be seen that the production method of the present invention can exert a good purifying effect on the silicon-based precursor and effectively remove metal ion impurities and high-boiling and low-boiling point substances in the silicon-based precursor. As a result of comparing Example 1 with Examples 1 to 4, it was found that the present invention can effectively improve the adsorption effect for metal ion impurities inside the silicon-based precursor by coating the outside of the adsorbent with a polymer coating.

As a result of comparing Example 2 and Comparative Examples 1 to 2, the adsorption effect for metal ion impurities inside the silicon-based precursor can be improved to some extent after coating the outside of the adsorbent with a nitrogen-doped matrix layer, but the nitrogen-doped matrix layer It was discovered that the adsorption effect for metal ion impurities can be greatly improved after being chemically bonded externally to sodium polyacrylate segments. It indicates that a synergistic effect can be formed between the nitrogen-doped matrix layer and the sodium polyacrylate segment.

As a result of comparing Example 2 and Comparative Example 3, in Comparative Example 3, because the amount of sodium acrylate added to the adsorbent D during the synthesis process was too large, it played a role in sealing the pores of the adsorbent, reducing the porosity, and further increasing the concentration of metal ion impurities. It was found that it affects the adsorption effect.

100: purification unit 110: purification tank
120: stirring device 121: driving motor
122: delivery rod 123: stirring paddle
130: Heating device 200: Rectification unit
210: Rectification column 220: Rectification packing
300: collection unit 310: collector
320: Caldwell 330: Low boiling point collector
400: pressure control unit 500: gas supply unit
510: Gas tank 520: Pressure control valve.

Claims (10)

As a method for purifying a silicon-based precursor,
The purification method is,
(S.1) dispersing the adsorbent in an ionic liquid to obtain an adsorption slurry;
(S.2) dissolving the industrial silicon-based precursor in the adsorption slurry, allowing the industrial silicon-based precursor to contact the adsorbent, so that the metal ion impurities in the industrial silicon-based precursor are adsorbed by the adsorbent; and
(S.3) After completion of adsorption, rectifying the crude silicon-based precursor to remove light components and heavy components in the silicon-based precursor and obtain an electronic grade silicon-based precursor. A method for purifying a silicon-based precursor, comprising: According to paragraph 1,
A method for purifying a silicon-based precursor, wherein the silicon-based precursor includes any one of octamethylcyclotetrasiloxane, trimethylsilane, tetramethylsilane, trimethylsilylamine, tetraethoxysilane, and diethoxymethylsilane. According to paragraph 1,
A method for purifying a silicon-based precursor, wherein the adsorbent in step (S.1) includes any one of activated carbon, porous alumina, silica gel powder, zeolite, or molecular sieve. According to claim 1 or 3,
In step (S.1), the outer surface of the adsorbent is also coated with a polymer coating;
The polymer coating body includes one layer of nitrogen-doped matrix layer coated on the outer surface of the adsorbent;
A method for purifying a silicon-based precursor, wherein the nitrogen-doped matrix layer is chemically bonded to the sodium polyacrylate segment from the outside. According to clause 4,
The method for producing the adsorbent is,
(1) Coating a layer of resin containing nitrogen atoms on the surface of the adsorbent;
(2) reacting the adsorbent coated with nitrogen atom resin with acryloyl chloride to graft acrylic acid groups onto the surface of the adsorbent coated with nitrogen atom resin, thereby forming a nitrogen doped matrix layer, that is, an intermediate, on the adsorbent;
(3) A method for purifying a silicon-based precursor, characterized in that the intermediate is copolymerized with sodium acrylate to obtain an adsorbent coated with a polymer coating. According to clause 4,
A method for purifying a silicon-based precursor, characterized in that the mass ratio of the intermediate and sodium acrylate in step (3) is less than 1:2. According to paragraph 1,
A method for purifying a silicon-based precursor, characterized in that the contact temperature between the industrial silicon-based precursor and the adsorbent in step (2) is 0 to 20°C. A purification system for purifying a silicon-based precursor, comprising:
The purification system includes at least:
A purification unit 100 including a purification tank 110 containing a substance, a stirring device 120 that serves to stir the substance inside the purification tank 110, and a heating device 130 that heats the purification tank 110;
A rectification unit 200 installed at the upper end of the purification tank 110 to rectify the silicon-based precursor obtained by evaporation within the chamber 110;
A collection unit 300 including a collector 310 connected to the pipe of the rectification unit 200 to collect the silicon-based precursor leaked from the rectification unit 200; and
A purification system for purifying a silicon-based precursor, comprising a pressure control unit (400) connected to the collector (310) pipe to control the internal pressure of the entire purification system. According to clause 8,
It further includes a gas supply unit 500 including a gas tank 510 for introducing inert gas into the purification tank 110, and a pressure control valve 520 for controlling the flow rate of the delivered inert gas flow. A purification system for purifying silicon-based precursors. According to clause 8,
A purification system for purifying a silicon-based precursor, characterized in that one cold well (320) is sleeved outside the collector (310).