Method for purifying disilane

Abstract

The invention discloses a method for purifying disilane, which comprises the following steps: A, filtration and adsorption treatment: mixed gas is sequentially introduced into at least one stage of filter and at least one stage of adsorber to remove solid impurities, the filter is selected from a porous ceramic filter, and the adsorber is selected from an activated carbon adsorber; b, primary rectification: introducing the filtered and adsorbed mixed gas into a heavy component removal tower for primary rectification to remove heavy component impurities, wherein the heavy component impurities are selected from gas impurities of which the molecular weight is greater than that of disilane; c, membrane separation: introducing the mixed gas subjected to primary rectification into a membrane separator, and enabling the mixed gas to pass through an organic polymer reverse osmosis membrane made of an inert material; and D, secondary rectification: introducing the mixed gas subjected to membrane separation treatment into a light component removal tower, and carrying out secondary rectification to remove monosilane. The method disclosed by the invention is simple to operate and few in working procedures, and is beneficial to quickly realizing high-quality separation and purification of disilane.

Description

Technical Field

[0001] The invention belongs to the technical field of disilane purification, and particularly relates to a method for purifying disilane. Background Art

[0002] Disilane is an inorganic compound with the chemical formula Si 2 H 6 , is a colorless, transparent, toxic gas with an unpleasant, irritating odor at room temperature and pressure. It has similar chemical properties to silane, but is more reactive than silane. It is more unstable than silane and decomposes slowly into silane and hydrogen at room temperature. It decomposes into SiH at 300-500°C. 4 、SinHm、H 2 , and also decomposes under light.

[0003] In the thin film deposition process of semiconductor integrated circuits, compared with other silicon source gases, it has the advantages of strong reactivity, high film uniformity, low deposition temperature, and fast film formation rate. At present, many integrated circuit chip manufacturers have widely used it in epitaxial growth, photolithography, chemical vapor deposition, semiconductor technology to grow silicon nitride film, silicon oxide film, etc. Therefore, in the electronics and microelectronics industry, high-purity disilane is the guarantee for the production of high-level and high-quality silicon wafers.

[0004] The main methods for preparing disilane include: reacting magnesium silicide with ammonium chloride to generate a small amount of disilane, reducing halogenated disilane to generate disilane, reacting magnesium silicide with inorganic acid to generate disilane, reacting magnesium silicide with ammonium chloride to generate disilane, and heating silane to convert it into disilane. Among them, the method of heating silane to convert it into disilane has relatively low raw material cost, a single type, and is relatively easy to purify after the reaction, but it also has the characteristics of producing a lot of solid powder and a low conversion rate.

[0005] Conventional distillation and purification methods will cause certain damage to the purification equipment and have certain environmental problems. The main reasons are: first, solid silicon is difficult to transport and transfer, which is not conducive to equipment operation; in addition, monosilane and the hydrogen obtained by the reaction have low boiling points, and the separation energy consumption is huge.

[0006] Therefore, in view of the above technical problems, it is necessary to provide a method for purifying disilane.

[0007] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0008] The object of the present invention is to provide a.

[0009] In order to achieve the above object, a technical solution provided by a specific embodiment of the present invention is as follows:

[0010] The method for purifying disilane comprises the following steps:

[0011] A. Filtration and adsorption treatment: the mixed gas is sequentially passed through at least one filter and at least one adsorber to remove solid impurities, wherein the filter is selected from a porous ceramic filter and the adsorber is selected from an activated carbon adsorber;

[0012] B. Primary distillation: the mixed gas after filtration and adsorption treatment is passed into a deweighting tower for primary distillation to remove heavy impurities, and the heavy impurities are selected from gas impurities with a molecular weight greater than disilane;

[0013] C. Membrane separation: The mixed gas after primary distillation is passed into the membrane separator and passes through the organic polymer reverse osmosis membrane made of inert material;

[0014] D. Secondary distillation: The mixed gas after membrane separation treatment is passed into a lightness removal tower for secondary distillation to remove monosilane.

[0015] In one or more embodiments of the present invention, the porous ceramic filter in step A is a hollow columnar structure with 2-5 micron micropores and one end open, wherein the micropores at least partially connect the inner and outer sides of the hollow columnar structure.

[0016] In one or more embodiments of the present invention, the raw material of the porous ceramic filter in step A is selected from alumina, ZrO 2 .

[0017] In one or more embodiments of the present invention, the activated carbon adsorber in step A is a packed column filled with activated carbon adsorption material.

[0018] In one or more embodiments of the present invention, the activated carbon adsorption material in step A is formed by stacking 0.2-1 mm porous particles.

[0019] In one or more embodiments of the present invention, the gas impurities in step B are at least selected from trisilane and butadienesilane.

[0020] In one or more embodiments of the present invention, the reverse osmosis membrane in step C is selected from: nylon-4 membrane, nylon-6 membrane and nylon-66 membrane. The membrane separation factor is 20, and the permeation flux is 800 GPU. After the membrane separation, the mixed gas has a disilane content of 2.13%, a monosilane content of 97.87%, and a hydrogen content of less than 1 ppm.

[0021] In one or more embodiments of the present invention, the working pressure in the membrane separation in step C is 8-15 bar.

[0022] In one or more embodiments of the present invention, disilane is prepared by the aforementioned method for purifying disilane.

[0023] Compared with the prior art, the method for purifying disilane of the present invention proposes a high-efficiency, low-cost separation and purification scheme specifically targeting the physical and chemical properties of disilane, thereby greatly improving the separation and purification effect of disilane gas. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0025] The method for purifying disilane of the present invention comprises the following steps:

[0026] A. Filtration and adsorption treatment: The purified raw gas, i.e., the mixed gas, is sequentially passed through at least one filter and at least one adsorber to remove solid impurities, wherein the filter is selected from alumina, ZrO 2 A porous ceramic filter, the filter is a hollow columnar structure with 2-5 micron micropores, one end of which is open, and the wall thickness is 2-10 mm, wherein the micropores at least partially connect the inner and outer sides of the hollow columnar structure, and the adsorber is selected from an activated carbon adsorber, which is a filling column filled with an activated carbon adsorption material formed by stacking 0.2-1 mm porous particles;

[0027] B. Primary distillation: the mixed gas after filtration and adsorption treatment is passed into a de-weighting tower for primary distillation to remove heavy impurities, the heavy impurities are selected from gas impurities with a molecular weight greater than disilane, the number of theoretical plates of the de-weighting tower 3 is 40, the reflux ratio is 2, the operating temperature is 20°C, and the operating pressure is 1 bar. After the primary distillation, the content of disilane in the mixed gas is 3.13%, the content of monosilane is 96.16%, the content of hydrogen is 1.95%, and the content of high boiling substances and silicon powder is less than 1ppm;

[0028] C. Membrane separation: The mixed gas after primary distillation is passed into a membrane separator with nylon-4 reverse osmosis membrane, nylon-6 reverse osmosis membrane and nylon-66 reverse osmosis membrane, and passes through an organic polymer reverse osmosis membrane made of inert materials; the working pressure is 8-15 bar, the membrane separation factor is 20, and the permeation flux is 800 GPU. After membrane separation, the content of disilane in the mixed gas is 2.13%, the content of monosilane is 97.87%, and the content of hydrogen is less than 1ppm.

[0029] D. Secondary distillation: The mixed gas after membrane separation treatment is passed into a lightness removal tower for secondary distillation to remove monosilane. The theoretical number of plates of the lightness removal tower is 40, the reflux ratio is 10, the operating temperature is -65°C, and the operating pressure is 1 bar. Monosilane is discharged from the top of the lightness removal tower and returned to the disilane reactor to continue to participate in the reaction. High-purity disilane with a purity greater than 99.999% is obtained in the kettle of the lightness removal tower. The contents of monosilane, hydrogen and trisilane in the high-purity disilane are less than 1ppm, and the contents of high boiling substances and silicon powder are less than 1ppm.

[0030] Through the above method, the present invention realizes a high-quality separation of electronic-grade gas and effectively reduces the separation cost, thereby strictly ensuring the large-scale application of the separation process and realizing the low-cost large-scale supply of electronic-grade disilane gas.

[0031] Including but not limited to the following embodiments, the reaction gas obtained by the monosilane cracking method is used as the raw gas for separation, and the raw gas may include: 3.16% silicon powder, 2.06% disilane, 1.67% hydrogen, 0.24% trisilane, 0.09% high boiling point, and the remainder of monosilane.

[0032] Example 1

[0033] The method for purifying disilane of the present embodiment comprises the following steps:

[0034] A. Filtration and adsorption treatment: the purified raw gas, i.e. the mixed gas, is sequentially passed through at least one filter and at least one adsorber to remove solid impurities, wherein the filter is selected from alumina porous ceramic filter, the filter is a hollow columnar structure with 2 micron micropores, one end of which is open, and the wall thickness is 2 mm, wherein the micropores at least partially connect the inner and outer sides of the hollow columnar structure, and the adsorber is selected from an activated carbon adsorber, which is a filling column filled with an activated carbon adsorption material formed by stacking 0.2-0.5 mm porous particles;

[0035] B. Primary distillation: the mixed gas after filtration and adsorption treatment is passed into a de-weighting tower for primary distillation to remove heavy impurities, the heavy impurities are selected from gas impurities with a molecular weight greater than disilane, the number of theoretical plates of the de-weighting tower 3 is 40, the reflux ratio is 2, the operating temperature is 20°C, and the operating pressure is 1 bar. After the primary distillation, the content of disilane in the mixed gas is 3.13%, the content of monosilane is 96.16%, the content of hydrogen is 1.95%, and the content of high boiling substances and silicon powder is less than 1ppm;

[0036] C. Membrane separation: The mixed gas after primary distillation is passed into a membrane separator with a nylon-4 reverse osmosis membrane, and passes through an organic polymer reverse osmosis membrane made of inert materials; the working pressure is 10 bar, the membrane separation factor is 20, and the permeation flux is 800 GPU. After membrane separation, the mixed gas has a disilane content of about 2.15%, a monosilane content of 97.85%, and a hydrogen content of less than 1 ppm.

[0037] D. Secondary distillation: The mixed gas after membrane separation treatment is passed into a lightness removal tower for secondary distillation to remove monosilane. The theoretical number of plates of the lightness removal tower is 40, the reflux ratio is 10, the operating temperature is -65°C, and the operating pressure is 1 bar. Monosilane is discharged from the top of the lightness removal tower and returned to the disilane reactor to continue to participate in the reaction. High-purity disilane with a purity greater than 99.999% is obtained in the kettle of the lightness removal tower. The contents of monosilane, hydrogen and trisilane in the high-purity disilane are less than 1ppm, and the contents of high boiling substances and silicon powder are less than 1ppm.

[0038] Example 2

[0039] The method for purifying disilane of the present embodiment comprises the following steps:

[0040] A. Filtration and adsorption treatment: the purified raw gas, i.e. the mixed gas, is sequentially passed through at least one filter and at least one adsorber to remove solid impurities, wherein the filter is selected from alumina porous ceramic filter, the filter is a hollow columnar structure with 3 micron micropores, one end of which is open, and the wall thickness is 6 mm, wherein the micropores at least partially connect the inner and outer sides of the hollow columnar structure, and the adsorber is selected from an activated carbon adsorber, which is a filling column filled with an activated carbon adsorption material formed by stacking 0.6-0.8 mm porous particles;

[0041] B. Primary distillation: the mixed gas after filtration and adsorption treatment is passed into a de-weighting tower for primary distillation to remove heavy impurities, the heavy impurities are selected from gas impurities with a molecular weight greater than disilane, the number of theoretical plates of the de-weighting tower 3 is 40, the reflux ratio is 2, the operating temperature is 20°C, and the operating pressure is 1 bar. After the primary distillation, the content of disilane in the mixed gas is 3.15%, the content of monosilane is 96.15%, the content of hydrogen is 1.94%, and the content of high boiling substances and silicon powder is less than 1ppm;

[0042] C. Membrane separation: The mixed gas after primary distillation is passed into a membrane separator with a nylon-4 reverse osmosis membrane, and passes through an organic polymer reverse osmosis membrane made of inert materials; the working pressure is 10 bar, the membrane separation factor is 20, and the permeation flux is 800 GPU. After membrane separation, the content of disilane in the mixed gas is about 2.12%, the content of monosilane is 97.88%, and the content of hydrogen is less than 1ppm.

[0043] D. Secondary distillation: The mixed gas after membrane separation treatment is passed into a lightness removal tower for secondary distillation to remove monosilane. The theoretical number of plates of the lightness removal tower is 40, the reflux ratio is 10, the operating temperature is -65°C, and the operating pressure is 1 bar. Monosilane is discharged from the top of the lightness removal tower and returned to the disilane reactor to continue to participate in the reaction. High-purity disilane with a purity greater than 99.999% is obtained in the kettle of the lightness removal tower. The contents of monosilane, hydrogen and trisilane in the high-purity disilane are less than 1ppm, and the contents of high boiling substances and silicon powder are less than 1ppm.

[0044] Example 3

[0045] The method for purifying disilane of the present embodiment comprises the following steps:

[0046] A. Filtration and adsorption treatment: the purified raw gas, i.e. the mixed gas, is sequentially passed through at least one filter and at least one adsorber to remove solid impurities, wherein the filter is selected from alumina porous ceramic filter, the filter is a hollow columnar structure with 5 micron micropores, one end of which is open, and the wall thickness is 10 mm, wherein the micropores at least partially connect the inner and outer sides of the hollow columnar structure, and the adsorber is selected from an activated carbon adsorber, which is a filling column filled with an activated carbon adsorption material formed by stacking 0.8-1 mm porous particles;

[0047] B. Primary distillation: the mixed gas after filtration and adsorption treatment is passed into a de-weighting tower for primary distillation to remove heavy impurities, the heavy impurities are selected from gas impurities with a molecular weight greater than disilane, the number of theoretical plates of the de-weighting tower 3 is 40, the reflux ratio is 2, the operating temperature is 20°C, and the operating pressure is 1 bar. After the primary distillation, the content of disilane in the mixed gas is 3.08%, the content of monosilane is 96.19%, the content of hydrogen is 1.97%, and the content of high boiling substances and silicon powder is less than 1ppm;

[0048] C. Membrane separation: The mixed gas after primary distillation is passed into a membrane separator with a nylon-4 reverse osmosis membrane, and passes through an organic polymer reverse osmosis membrane made of inert materials; the working pressure is 10 bar, the membrane separation factor is 20, and the permeation flux is 800 GPU. After membrane separation, the content of disilane in the mixed gas is about 2.17%, the content of monosilane is 97.83%, and the content of hydrogen is less than 1ppm.

[0049] D. Secondary distillation: The mixed gas after membrane separation treatment is passed into a lightness removal tower for secondary distillation to remove monosilane. The theoretical number of plates of the lightness removal tower is 40, the reflux ratio is 10, the operating temperature is -65°C, and the operating pressure is 1 bar. Monosilane is discharged from the top of the lightness removal tower and returned to the disilane reactor to continue to participate in the reaction. High-purity disilane with a purity greater than 99.999% is obtained in the kettle of the lightness removal tower. The contents of monosilane, hydrogen and trisilane in the high-purity disilane are less than 1ppm, and the contents of high boiling substances and silicon powder are less than 1ppm.

[0050] Example 4

[0051] The method for purifying disilane of the present embodiment comprises the following steps:

[0052] A. Filtration and adsorption treatment: The purified raw gas, i.e. the mixed gas, is sequentially passed through a primary filter and a primary adsorber to remove solid impurities, wherein the filter is selected from ZrO 2 A porous ceramic filter, the filter is a hollow columnar structure with 5 micron micropores and one end open, the wall thickness is 10 mm, wherein the micropores at least partially connect the inner and outer sides of the hollow columnar structure, and the adsorber is selected from an activated carbon adsorber, which is a filling column filled with an activated carbon adsorption material formed by stacking 0.8-1 mm porous particles;

[0053] B. Primary distillation: the mixed gas after filtration and adsorption treatment is passed into a de-weighting tower for primary distillation to remove heavy impurities, the heavy impurities are selected from gas impurities with a molecular weight greater than disilane, the number of theoretical plates of the de-weighting tower 3 is 30, the reflux ratio is 2, the operating temperature is 20°C, and the operating pressure is 1 bar. After the primary distillation, the content of disilane in the mixed gas is 3.21%, the content of monosilane is 96.1%, the content of hydrogen is 1.93%, and the content of high boiling substances and silicon powder is less than 1ppm;

[0054] C. Membrane separation: The mixed gas after primary distillation is passed into a membrane separator with a nylon-6 reverse osmosis membrane, and passes through an organic polymer reverse osmosis membrane made of inert materials; the working pressure is 15 bar, the membrane separation factor is 20, and the permeation flux is 1000 GPU. After membrane separation, the mixed gas has a disilane content of 2.43%, a monosilane content of 97.57%, and a hydrogen content of less than 1ppm.

[0055] D. Secondary distillation: the mixed gas after membrane separation treatment is passed into a lightness removal tower for secondary distillation to remove monosilane. The theoretical plate number of the lightness removal tower is 45, the reflux ratio is 15, the operating temperature is -65°C, and the operating pressure is 1 bar. The monosilane is discharged from the top of the lightness removal tower and returned to the disilane reactor to continue to participate in the reaction. High-purity disilane with a purity greater than 99.999% is obtained in the kettle of the lightness removal tower. The contents of monosilane, hydrogen and trisilane in the high-purity disilane are less than 0.5ppm, and the contents of high boiling substances and silicon powder are less than 0.5ppm.

[0056] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0057] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for purifying disilane, characterized in that: The steps include: A. Filtration and adsorption treatment: the mixed gas is sequentially passed through at least one filter and at least one adsorber to remove solid impurities, wherein the filter is selected from a porous ceramic filter and the adsorber is selected from an activated carbon adsorber; B. Primary distillation: passing the mixed gas after filtration and adsorption treatment into a deweighting tower for primary distillation to remove heavy impurities, wherein the heavy impurities are selected from gas impurities with a molecular weight greater than that of disilane; C. Membrane separation: The mixed gas after primary distillation is passed into the membrane separator and passes through the organic polymer reverse osmosis membrane made of inert material; D. Secondary distillation: The mixed gas after membrane separation treatment is passed into a lightness removal tower for secondary distillation to remove monosilane.

2. The method for purifying disilane according to claim 1, characterized in that: The porous ceramic filter in step A is a hollow columnar structure with 2-5 micron micropores and one end open, wherein the micropores at least partially connect the inner and outer sides of the hollow columnar structure.

3. The method for purifying disilane according to claim 2, characterized in that: The raw material of the porous ceramic filter in step A is selected from alumina and ZrO2.

4. The method for purifying disilane according to claim 1, characterized in that: The activated carbon adsorber in step A is a filling column filled with activated carbon adsorption material.

5. The method for purifying disilane according to claim 4, characterized in that: The activated carbon adsorption material in step A is formed by the accumulation of 0.2-1 mm porous particles.

6. The method for purifying disilane according to claim 1, characterized in that: The gas impurities in step B are at least selected from trisilane and butadienesilane.

7. The method for purifying disilane according to claim 1, characterized in that: The reverse osmosis membrane in step C is selected from: nylon-4 membrane, nylon-6 membrane and nylon-66 membrane.

8. The method for purifying disilane according to claim 7, characterized in that: The working pressure in the membrane separation in step C is 8-15 bar.

9. Disilane prepared by the method for purifying disilane according to any one of claims 1 to 8.