A method for removing trace chloride salts from aminosilane

Abstract

The invention discloses a method for removing trace chloride salts in aminosilane, comprising the following steps: S1 provides a resin fixed bed, wherein an ion exchange resin is fixed in the resin fixed bed; S2 passes crude aminosilane liquid into the resin fixed bed through a sealed pipe, allowing the aminosilane liquid to flow through the fixed bed and fully contact with the resin inside; S3 receives the aminosilane liquid flowing out of the resin fixed bed, and obtains a crude aminosilane product whose chlorine content meets the electronic grade standard. The invention has simple process technology, strong stability, wide applicability, and is convenient and easy to operate, which can match the existing synthesis and purification process, and adopts a sustainably regenerated weakly alkaline anion exchange resin, which has excellent desalination effect and is economical and environmentally friendly.

Description

Technical Field

[0001] The invention relates to the technical field of silicon-based precursor purification, and more particularly to a method for removing trace amounts of chloride salts in aminosilane. Background Art

[0002] Aminosilane compounds, such as trimethylsilane, diisopropylaminosilane, bis(diethylamino)silane, etc., are precursor materials for silicon-based film formation, which can be used in various deposition processes including atomic layer deposition (ALD) and chemical vapor deposition (CVD). They are precursor materials for silicon nitride or silicon oxynitride layer film formation in chip preparation in the semiconductor industry. With the vigorous development of the semiconductor industry in recent years and the market's increasingly high requirements for semiconductor device performance, aminosilane precursor materials have been valued by major semiconductor manufacturers for their excellent properties, and the demand has been rising year by year.

[0003] At present, most of the industrial production of aminosilane uses chlorosilane and amine as raw materials, which are introduced into the reactor in condensed or gaseous state for reaction to generate the target product and the by-product chloride salt, and then the target product and the chloride salt are separated through evaporation / filtration process in order to obtain a pure target product. However, in fact, such chloride salts have the characteristics of easy decomposition, light weight, easy dispersion, easy adsorption, and micro-dissolution in the target product. Therefore, there are still trace amounts of chloride salts (above 4000ppm) remaining in the target product separated by evaporation and filtration process, which affects the terminal quality of the product. Moreover, under long-term reaction conditions, chloride salts will cause the decomposition of the target product and reduce the overall yield.

[0004] In order to remove these trace chloride salts in the prior art, membrane separation, distillation, adsorption, chemical reaction and other methods are usually used for purification. However, these methods are usually cumbersome and require a lot of consumables, which not only greatly increases the cost, but also causes problems such as difficulty in cleaning the device after desalination.

[0005] Patent CN118221718A discloses a method for purifying aminosilane, which fills a distillation column with metal oxides and anionic polymers containing carbonyl groups, and allows the aminosilane to contact with the adsorption filler during the distillation process. Impurities and metal ions in the aminosilane can be effectively adsorbed by the adsorption filler filled in the distillation column, thereby ultimately achieving electronic grade quality. This method integrates the impurity removal and purification processes in the distillation column at the same time, with a high degree of coupling, which increases the instability of the system, and the adsorption filler and resin used for impurity removal are difficult to replace and recycle in the distillation column after reaching the adsorption limit.

[0006] Patent CN118221717A discloses a method for purifying diisopropylaminosilane, which is to fill a distillation column with a porous cellulose substrate containing polyamino compounds and halogen-containing alkane segments, and to react with the chloride in the aminosilane to form an organic amine before the polyamino compounds during the distillation process, and then adsorb and fix the organic amine through the porous cellulose substrate containing the halogen-containing alkane segments. This method has the same problem. The distillation column integrates the impurity removal and purification processes at the same time, and the coupling degree is high, which increases the instability of the system. After reaching the adsorption limit, the adsorption filler and cellulose substrate used for impurity removal are difficult to replace and recycle in the distillation column. In addition, small molecular polyamino compounds may desorb and dissolve in the target product or solvent, which poses a risk of introducing impurities, and the halogen-containing alkane segments, while adsorbing and fixing the organic amine, also pose a risk of introducing halogen impurities into the distillation product again. Summary of the invention

[0007] 1. Technical issues to be resolved

[0008] In view of the problems existing in the prior art, the present invention provides a method for removing trace chloride salts in aminosilane, so as to solve the technical problem that the prior art cannot remove trace chloride salts in aminosilane simply, efficiently and at low cost.

[0009] (II) Technical solution

[0010] To achieve the above object, the present invention provides the following technical solution: a method for removing trace chloride salts in aminosilane, comprising the following steps:

[0011] S1: providing a resin fixed bed, wherein an ion exchange resin is fixed in the resin fixed bed;

[0012] The ion exchange resin is a weakly basic anion exchange resin, and its general structural formula is shown below. The matrix type is styrene, and the substituent on the benzene ring is CH2NR2, where the R group is H, CH3, (CH2) n CH3, [(CH2) n NH] m One or more of H, where n, m = 1-5;

[0013] S2: The crude aminosilane liquid is passed through a sealed pipe into a resin fixed bed, and the aminosilane liquid containing trace amounts of chloride salts is allowed to flow through the fixed bed, and fully contact the resin inside through the gaps between the resins, so that the amine salts in the aminosilane exchange anions with the weakly basic groups on the resin, and the chlorine is fixed in the resin, thereby achieving the purpose of removing the halide. Taking ammonium chloride as an example, the specific ion exchange reaction formula is as follows: PS-CH2NR2+NH4Cl→PS-CH2NHR2Cl+NH3;

[0014] The ion exchange process only fixes chloride ions on the resin and generates amines as reaction raw materials without introducing other impurities.

[0015] S3: receiving the aminosilane liquid flowing out from the resin fixed bed, that is, obtaining a crude aminosilane product whose chlorine content meets the electronic grade standard, and further distilling and purifying it to obtain an electronic grade aminosilane product.

[0016] When the anion exchange resin in the fixed bed reaches the upper limit of exchange and becomes inactivated, it can be eluted with alkaline solution to be regenerated and reused.

[0017] The present invention is further configured such that the ion exchange resin in the resin fixed bed is a gel type, a macroporous type, or a mixture of the two types, which needs to be determined according to the specific aminosilane product and the chlorine content.

[0018] The present invention is further configured such that the weakly alkaline ion exchange resin in the resin fixed bed is a mixture of one or more resin particles, which needs to be determined according to the specific aminosilane product and chlorine content.

[0019] The present invention is further configured such that the residence time of the crude aminosilane in the resin fixed bed in the step S2 is 5-3000s.

[0020] The present invention is further configured such that the crude product feed temperature in the step S2 is 15-50° C. and the operating temperature is room temperature.

[0021] The present invention is further configured such that the aminosilane is aminosilane such as trimethylsilylamine, diisopropylaminosilane, bis(diethylamino)silane, etc.

[0022] (III) Beneficial effects

[0023] Compared with the prior art, the present invention provides a method for removing trace chloride salts in aminosilane, which has the following beneficial effects:

[0024] 1. The process technology of the present invention is simple. A separate desalination process is set up through a resin fixed bed to reduce the coupling degree with other sections. It has strong stability, wide applicability, and is convenient and easy to operate, without the need to make major changes to the existing infrastructure.

[0025] 2. By using sustainably regenerated weakly alkaline anion exchange resin, it is economical and environmentally friendly while ensuring good desalination effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A flow chart of a method for removing trace chloride salts from aminosilane in the present invention; DETAILED DESCRIPTION

[0027] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0029] See also Figure 1 , a method for removing trace chloride salts in aminosilane, comprising the following steps:

[0030] S1: providing a resin fixed bed, wherein an ion exchange resin is fixed in the resin fixed bed;

[0031] The ion exchange resin is a weakly basic anion exchange resin, and its general structural formula is shown below. The matrix type is styrene, and the R group is H, CH3, (CH2) n CH3, [(CH2) n NH] m One or more of H, where n, m = 1-5;

[0032] S2: The crude aminosilane liquid is passed through a sealed pipe into a resin fixed bed, and the aminosilane liquid containing trace amounts of chloride salts is allowed to flow through the fixed bed, and fully contact the resin inside through the gaps between the resins, so that the amine salts in the aminosilane exchange anions with the weakly basic groups on the resin, and the chlorine is fixed in the resin, thereby achieving the purpose of removing the halide. Taking ammonium chloride as an example, the specific ion exchange reaction formula is as follows: PS-CH2NR2+NH4Cl→PS-CH2NHR2Cl+NH3;

[0033] The ion exchange process only fixes chloride ions on the resin and generates amines as reaction raw materials without introducing other impurities.

[0034] S3: receiving the aminosilane liquid flowing out from the resin fixed bed, that is, obtaining a crude aminosilane product whose chlorine content meets the electronic grade standard, and further distilling and purifying it to obtain an electronic grade aminosilane product.

[0035] When the anion exchange resin in the fixed bed reaches the upper limit of exchange and becomes inactivated, it can be eluted with alkaline solution to be regenerated and reused.

[0036] In a further embodiment of the present invention, the ion exchange resin in the resin fixed bed is a gel type, a macroporous type, or a mixture of the two types, which needs to be determined according to the specific aminosilane product and the chlorine content; the weakly alkaline ion exchange resin in the resin fixed bed is a mixture of one or more resin particles, which needs to be determined according to the specific aminosilane product and the chlorine content; the residence time of the aminosilane crude product in the step S2 in the resin fixed bed is 5-3000s; the crude product feed temperature in the step S2 is 15-50°C, and the working temperature is room temperature; the aminosilane is aminosilane such as trimethylsilylamine, diisopropylaminosilane, bis(diethylamino)silane, etc.

[0037] Pretreatment and regeneration of weakly basic anion exchange resin:

[0038] (1) Pretreatment of new resin: Fill the resin into the resin fixed bed, pass pure water or 10wt% dilute alkali solution to circulate and clean the resin fixed bed for 4-7 hours, then use pure water to continue flushing for 1-2 hours to end the cleaning, heat the resin fixed bed to 50-70℃, and dry it under negative pressure for 24 hours before putting it into use.

[0039] (2) Resin regeneration: The residual aminosilane products in the resin fixed bed are eluted with organic solvents in a continuous cycle for 12 hours to completely elute the aminosilane. The organic solvents in the resin fixed bed are further eluted with alcohol ether solvents, and then cleaned with water. Finally, an ammonia alkaline solution equivalent to 1.5 times the resin anion is passed through, and the resin is soaked at 30-50℃ for regeneration for 8-12 hours. The alkaline solution is discharged, and the resin is rinsed with pure water for 1-2 hours to complete the cleaning. The resin fixed bed is heated to 50-70℃, vacuum-dried for 24 hours, and then it can be put into use.

[0040] Example 1

[0041] The crude trisilylamine (component content: 91.1wt% trisilylamine, 6.0wt% disilylamine, 0.65wt% ammonium chloride, 2.25wt% other silicon nitrogen polymers) was introduced into the resin fixed bed. The temperature was controlled at 35°C. The residence time of trisilylamine in the fixed bed was 300±30s. The resin structure used was as follows:

[0042] The substituent on the benzene ring is CH2NH2.

[0043] Example 2

[0044] The difference between Example 2 and Example 1 is that the resins used are two mixed types, and the specific structural formula is as follows:

[0045] The substituents on the benzene ring are CH2NH2 and the substituents on the benzene ring are CH2NHCH3.

[0046] Example 3

[0047] The difference between Example 3 and Example 2 is that the residence time is 600±30s.

[0048] Example 4

[0049] The crude diisopropylaminosilane (component content: 95.3wt% diisopropylaminosilane, 3.87wt% diisopropylamine, 0.83wt% diisopropylamine hydrochloride) was introduced into the resin fixed bed, the temperature was controlled at 40°C, the residence time of trisilylamine in the fixed bed was 600±30s, and the resin type used was two mixed types, the specific structural formula is as follows:

[0050] The substituent on the benzene ring is CH2N(CH3)2 and the substituent on the benzene ring is CH2N(CH2CH3)2.

[0051] Example 5

[0052] The difference between Example 5 and Example 4 is that the resin types used are three mixed types, and the specific structural formula is as follows:

[0053] The substituents on the benzene ring are CH2NH2, CH2N(CH3)2, CH2N(CH2CH3)2.

[0054] Example 6

[0055] The crude bis(diethylamino)silane (component content: 97.46wt% bis(diethylamino)silane, 2.1wt% diethylamine, 0.44wt% diethylamine hydrochloride) was introduced into the resin fixed bed, the temperature was controlled at 40°C, the residence time of trisilylamine in the fixed bed was 600±30s, and the specific structural formula of the resin used was as follows:

[0056] The substituent on the benzene ring is CH2NH(CH2CH2NH)CH3.

[0057] Example 7

[0058] The difference between Example 7 and Example 6 is that the resin types used are three mixed types, and the specific structural formula is as follows:

[0059] The substituents on the benzene ring are CH2NHCH2CH2CH3.

[0060] Comparative Example 1

[0061] The crude trisilylamine (component content: 91.1wt% trisilylamine, 6.0wt% disilylamine, 0.65wt% ammonium chloride, 2.25wt% other silicon nitrogen polymers) is introduced into a stainless steel filler fixed bed, the temperature is controlled at 35°C, and the residence time of trisilylamine in the fixed bed is 600±30s.

[0062] Comparative Example 2

[0063] The crude diisopropylaminosilane (component content: 95.3wt% diisopropylaminosilane, 3.87wt% diisopropylamine, 0.83wt% diisopropylamine hydrochloride) was introduced into a fixed bed filled with stainless steel filler. The temperature was controlled at 40°C, and the residence time of trisilylamine in the fixed bed was 600±30s.

[0064] Comparative Example 3

[0065] The crude bis(diethylamino)silane (component content: 97.46wt% bis(diethylamino)silane, 2.1wt% diethylamine, 0.44wt% diethylammonium hydrochloride) was introduced into a fixed bed filled with stainless steel filler. The temperature was controlled at 40°C, and the residence time of trisilylamine in the fixed bed was 600±30s.

[0066] The salt concentration test results in Examples 1-7 and Comparative Examples 1-3 are shown in Table 1 below.

[0067] Table 1

[0068] Salt concentration (ppm) Example 1 56.8 Example 2 21.4 Example 3 4.1 Example 4 15.5 Example 5 4.2 Example 6 14.2 Example 7 5.5 Comparative Example 1 5531.1 Comparative Example 2 6734.9 Comparative Example 3 4021.7

[0069] It can be seen from the data in the above table that the desalination method of the present invention can effectively remove trace chloride salts in aminosilane to reach the electronic grade level.

[0070] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for removing trace chloride salts from aminosilane, characterized in that: The following steps are involved: S1: providing a resin fixed bed, wherein an ion exchange resin is fixed in the resin fixed bed; The ion exchange resin is a weakly basic anion exchange resin, and its structural formula is shown below. The matrix type is styrene, and the substituent on the benzene ring is CH2NR2, wherein the R group is H, CH3, (CH2) n CH3, [(CH2) n NH] m H one or more, wherein n, m = 1-5; the ion exchange resin in the fixed resin bed is a gel type, a macroporous type, or a mixture of the two; S2: The crude aminosilane liquid is passed through a sealed pipe into a resin fixed bed, and the aminosilane liquid containing trace amounts of chloride salt flows through the fixed bed, and is fully in contact with the resin inside through the gaps between the resins, so that the amine salt in the aminosilane and the weakly basic group on the resin undergo anion exchange, and the chlorine is fixed in the resin, thereby achieving the purpose of removing the chloride salt. When the chloride salt is ammonium chloride, the specific ion exchange reaction formula is as follows: PS-CH2NR2+NH4Cl→PS-CH2NHR2Cl+NH3; the aminosilane is trimethylsilylamine, diisopropylaminosilane or bis(diethylamino)silane; The ion exchange process only fixes chloride ions on the resin and generates amines as reaction raw materials without introducing other impurities. The residence time of the crude aminosilane in the resin fixed bed is 300-3000s; S3: receiving the aminosilane liquid flowing out from the resin fixed bed, that is, obtaining a crude aminosilane product whose chlorine content meets the electronic grade standard, and further distilling and purifying it to obtain an electronic grade aminosilane product.

2. A method for removing trace chloride salts in aminosilane according to claim 1, characterized in that: The weakly alkaline ion exchange resin in the resin fixed bed is a mixture of one or more resin particles.

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