Vacuum gas phase synthesis method of dialkyl acetylene compound and application thereof

Abstract

The application discloses a kind of dialkyl acetylene compound's reduced pressure gas phase synthesis method and its application, wherein, dialkyl acetylene compound's structural formula is R1-C≡C-R2, R1 and R2 each selects C1-C9 straight chain or branched alkyl.The application adopts the reduced pressure gas phase synthesis method of two-step elimination mechanism of o-dihalogen alkane, and the apparent activation energy of ethenyl halide elimination is reduced by pressure-catalysis synergistic effect, and the high selectivity synthesis of dialkyl acetylene compound is realized under mild conditions;The use of dialkyl acetylene compound in semiconductor manufacturing is used as the selective surface modification layer in advanced interconnection structure.

Description

Technical Field

[0001] This invention belongs to the field of electronic chemical materials preparation technology, and specifically relates to a method for the depressurized gas-phase synthesis of dialkyl acetylene compounds and its application. Background Technology

[0002] As Moore's Law approaches its physical limits, the resistance-capacitance (RC) delay of copper interconnects has become a key bottleneck restricting chip performance. In advanced processes of 7nm and below, via contact resistance accounts for more than 40% of the total interconnect resistance. Its main sources include the Schottky barrier caused by the copper surface oxide layer, interface scattering between the tantalum / tantalum nitride barrier layer and copper, and residual dielectric at the bottom of the via caused by photolithography alignment errors.

[0003] To address this challenge, the industry has developed "bottomless contact" and "self-aligned via" (SAV) technologies. The core of these technologies lies in achieving differentiated treatment of metal surfaces such as copper / cobalt and silicon oxide / low-k dielectric surfaces—that is, not depositing a barrier layer on the metal surface to reduce resistance, while depositing a barrier layer normally on the dielectric surface to ensure reliability.

[0004] The realization of this differentiated treatment relies on organic functional materials with selective surface affinity. A high-purity material is needed for the application of sacrificial layer materials. Dialkylacetylene compounds (general formula R1-C≡C-R2) exhibit ideal interface regulation properties due to their unique molecular structure: the carbon-carbon triple bonds in the molecule can specifically coordinate with empty d orbitals on transition metal surfaces, forming a directionally ordered self-assembled monolayer; the alkyl chain provides hydrophobic steric hindrance, effectively blocking the vapor deposition of ALD / CVD precursors; they are chemically inert to oxide / nitride surfaces; and they can be completely removed through mild pyrolysis or solvent extraction, leaving no carbon residue or metal contamination. Therefore, these compounds have irreplaceable application value as sacrificial layer materials or selectively deposited barrier layers in advanced interconnect processes.

[0005] However, existing technologies for the synthesis of dialkylacetylenes suffer from the following problems: While common liquid-phase methods (such as Glaser coupling and sodium ammonia method) operate at mild temperatures, they inevitably introduce transition metal ions (Cu, Na, etc.) or nitrogen-containing solvents, leading to excessive ion residues and failing to meet the stringent requirements for metal impurities in semiconductor precursor materials. Atmospheric-pressure gas-phase methods, although solvent-free synthesis is possible, require temperatures above 300°C to drive the elimination of vinyl halides, resulting in severe product cracking, polymerization, and rapid catalyst deactivation due to carbon deposition. Therefore, there is an urgent need to develop a novel continuous gas-phase synthesis method that is free of transition metal catalysis and nitrogen-containing solvents, and can be efficiently carried out at medium to low temperatures (<280°C). Summary of the Invention

[0006] To address the problems in related technologies, this invention proposes a method for the vacuum gas-phase synthesis of dialkyl acetylene compounds and its application, thereby overcoming the aforementioned technical problems existing in the prior art.

[0007] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: A method for vacuum gas-phase synthesis of dialkylacetylene compounds, wherein the dialkylacetylene compounds have the structure shown in formula (I): R1—C≡C—R2 (I); R1 and R2 are each selected from C1-C9 straight-chain or branched alkyl groups.

[0008] Includes the following steps: (1) Precursor decompression vaporization: The ortho-dihaloalkane feedstock having the structure of formula (II) is gasified and mixed with an inert carrier gas to obtain a mixed feedstock gas; R1—CHX—CHX—R2 (II); Where X is Cl, Br or I; R1 and R2 are each selected from C1-C9 straight-chain or branched alkyl groups.

[0009] (2) Two-step continuous removal of hydrogen halides: The mixed feed gas obtained in step (1) is fed into a vacuum reactor loaded with a catalyst, and a two-step continuous elimination reaction is carried out to remove hydrogen halide under an absolute pressure of 10-50 Torr. (3) Separation and purification: The product-containing gas stream obtained in step (2) is subjected to reduced pressure condensation in a -30°C to -60°C cold trap to collect the crude product; the crude product is then subjected to short-path molecular distillation (10... -3 -10 -2 Torr) separates unreacted raw materials, hydrogen halide byproducts and target product to obtain purified product; (4) Inert atmosphere collection: The purified product obtained in step (3) was collected in a pre-cleaned sealed container under inert gas protection to obtain a high-purity dialkylacetylene compound with a single metal ion impurity of <100 ppb. An inert gas was used to prevent the product from contacting water and oxygen in the air, ensuring product quality and better meeting quality requirements in later customer applications.

[0010] As a preferred technical solution, the dihaloalkane raw material is selected from dihalooctane derivatives, dihalohexane derivatives, etc.

[0011] As a preferred technical solution, in step (1), the ortho-dihaloalkane feedstock is vaporized at 60-170°C under an absolute pressure of 10-50 Torr.

[0012] As a preferred technical solution, in step (1), the inert carrier gas is argon or nitrogen, and the inert carrier gas has a molar ratio of 40:1 to 120:1 with the ortho-dihaloalkane raw material.

[0013] As a preferred technical solution, in step (2), the catalyst is selected from a composite system of alkali metal carbonates, hydroxides, or alkoxides supported on a high specific surface area oxide support; preferably, the catalyst is Cs2CO3 / γ-Al2O3, KOH / Al2O3, or NaNH2 / molecular sieve, with an alkali loading of 10-30wt% and a support specific surface area >250 m². 2 / g. (Its Hammett function (H0) is greater than 26;) As a preferred technical solution, the elimination step in step (2) includes: First step elimination: Temperature 140-180℃, residence time 5.0 seconds-10.0 seconds, to cause the first HX removal of compound (II) to generate vinyl halide intermediate R1-CH=CX-R2; The second elimination step involves a temperature of 220-280℃ and a residence time of 3.0-8.0 seconds. Under the influence of the ultra-alkaline sites on the catalyst surface, the vinyl halide intermediate undergoes a second de-HX reaction, generating a dialkyl acetylene of formula (I).

[0014] As a preferred technical solution, in step (3), the cold trap uses a liquid nitrogen / ethanol mixed bath (-50℃ to -60℃) to ensure efficient condensation of the product under reduced pressure and prevent blockage of the pipeline.

[0015] The present invention also proposes a dialkylacetylene compound, which is a compound having the structure shown in formula (I) prepared by the aforementioned reduced pressure gas phase synthesis method, wherein R1 and R2 are C1-C9 alkyl groups, the product purity is >99%, the content of single metal ion impurities is <100 ppb, and the residual halide ion is <5 ppb.

[0016] This invention also proposes the use of dialkylacetylene compounds in semiconductor manufacturing as selective surface modification layers in advanced interconnect structures. Specifically, the dialkylacetylene compound is used to form coordination bonds with the d-orbitals of a metal layer Cu or Co, without bonding with the SiOx or SiNx thin film. This ultimately forms a self-resisting layer on the Cu or Co metal surface, creating steric hindrance and a hydrophobic layer that hinders subsequent film deposition. With subsequent heating, the coordination bonds of the self-assembled layer break, allowing it to be removed. Subsequent metal electrodes can then be directly deposited on the underlying metal, thereby reducing resistance.

[0017] The present invention has the following beneficial effects: (1) The depressurized gas-phase synthesis method using the two-step elimination mechanism of ortho-dihaloalkanes reduces the apparent activation energy of vinyl halide elimination through the pressure-catalysis synergistic effect, and achieves highly selective synthesis of dialkyl acetylene compounds under mild conditions; (2) The use of dialkyl acetylene compounds in semiconductor manufacturing as selective surface modification layers in advanced interconnect structures. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart illustrating the deposition process involving dialkyl acetylene compounds of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0021] In the description of this invention, it should be understood that the terms "opening", "upper", "lower", "top", "middle", "inner", etc., which indicate orientation or positional relationship, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the invention.

[0022] The dialkyl acetylene compounds of the present invention have the structure shown in formula (I): R1—C≡C—R2 (I); R1 and R2 are each selected from C1-C9 straight-chain or branched alkyl groups.

[0023] A detailed explanation of the principles behind the synthesis technique: (1) Structural advantages of ortho-dihaloalkanes This invention uses a vicinal dihalide of formula (II) as a precursor: R1-CHX-CHX-R2 (II) This structure ensures the formation of the R1-C≡C-R2 backbone after two eliminations. X is preferably Br or I, because the C-Br / I bond energy is moderate, ensuring elimination activity while avoiding excessive cleavage.

[0024] (2) The promoting effect of decompression on elimination reaction Both elimination steps involve an increase in the number of molecules (1 mol → 2 mol). According to Le Chatelier's principle, reducing the system pressure to 10⁻⁵ Torr (1 / 15 to 1 / 50 of atmospheric pressure) can: significantly lower the reaction temperature (boiling point decreases by 40-60 °C), allowing the reaction to proceed in the gas phase without solvent; shift the HX removal equilibrium towards the product side; and increase the gas-phase diffusion coefficient, ensuring that the generated HX is immediately carried away from the reaction zone, avoiding reversible addition (R₁≡C₁R₂ + HX → R₁₁CH=CX₁R₂).

[0025] (3) Two-step temperature gradient and confined catalysis To address the kinetic differences that need to be eliminated in two steps, this invention designs a two-stage temperature-controlled reactor: First stage (140-180℃): Completes the first elimination to form a vinyl halide. This temperature is sufficient to activate the CX bond, but below the product boiling point to prevent excessive volatilization.

[0026] The second stage (220-280℃): The second elimination occurs on the surface of a superbase catalyst (such as Cs2CO3 / γ-Al2O3). Generally, the catalyst support (pore size 2-10 nm) produces a confinement effect: the surface electric field inside the pores enhances the base strength (Hammett function (H0) > 26), which can abstract vinyl hydrogen at lower temperatures; the trans-coplanar conformation is more easily formed in the pores, promoting elimination; and the reduced pressure lowers the boiling point of the vinyl halogen, ensuring its effective diffusion from the gas phase to the catalyst surface.

[0027] (4) Remove quickly to prevent further reaction With ultra-high ratio carrier gas dilution (40:1-120:1), the apparent gas flow rate reaches 1.0-3.0 m / s. The material stays in the second high-temperature zone for less than 8 seconds. After the product is generated, it is carried away by the carrier gas, avoiding polymerization and cracking caused by prolonged exposure to high temperature.

[0028] In the following embodiments, pressure control uses a high-precision vacuum pump set (dry screw pump + Roots pump), temperature control uses a PID temperature controller (accuracy ±0.5℃), and metal ion detection uses ICP-MS.

[0029] Example 1 Synthesis of compounds with R1=C3H7 and R2=C4H9 under reduced pressure in formula (I).

[0030] The specific structural formula is C3H7-C≡C-C4H9 (C9 product); (1) Precursor preparation and vaporization: C3H7-CHX-CHX-C4H9 (a C9 compound) with the structure of formula (II) was used as the raw material. The raw material was delivered to the vaporization chamber at a rate of 4.5 g / min using a precision metering pump. The system pressure was maintained at 25 Torr and the vaporization temperature was set at 115 °C (the boiling point drops to about 120 °C under this reduced pressure). Ultrapure argon (flow rate 5.0 L / min, purity >99.999%) was used as the carrier gas, and the molar ratio of carrier gas to raw material was about 85:1.

[0031] (2) Two-step continuous dehydrohalogenation: A tubular fixed-bed reactor was used (material: Hastelloy C-276, inner diameter 12 mm, tube length 1000 mm, loaded with 400 g of Cs2CO3 / γ-Al2O3 catalyst, Cs loading 22 wt%, support specific surface area 380 m²). 2 / g).

[0032] System pressure is maintained at 22 Torr.

[0033] First stage (first elimination): temperature 155±3℃, residence time 7 seconds. In this zone, the raw material undergoes its first dehydrogenation, mainly producing the vinyl halide intermediate C3H7-CH=CX-C4H9; Second stage (second elimination): Temperature 245±3℃, residence time 5 seconds. Under the action of a superbase site, the vinyl halide intermediate C3H7-CH=CX-C4H9 undergoes a second E2 elimination to produce the target product C3H7-C≡C-C4H9 (Formula I).

[0034] (3) Real-time separation and purification: The reactor outlet gas stream passes through a -55℃ cold trap to collect the crude product.

[0035] The crude product was subjected to short-path molecular distillation: The distillation pressure was 6 × 10⁻⁶. -3 Torr; Evaporation surface temperature: 105℃; Condensation surface temperature: 45℃; The resulting product is a colorless, transparent liquid with a characteristic hydrocarbon odor.

[0036] (4) Results Analysis: ; Mechanism verification: A sampling port was set in the middle section of the reactor (first stage outlet), and the concentration of vinyl halide intermediate was detected to reach its peak (about 35% of the feed conversion rate); at the second stage outlet, the concentration of this intermediate dropped to <1%, and the target alkyne became the main product, confirming the two-step elimination mechanism.

[0037] Example 2 Synthesis of compounds (C8 products) where R1 = R2 = C3H7 in formula (I) Synthesize compounds having the structure of formula (I), wherein both alkyl groups are n-propyl (total C8 carbons).

[0038] (1) The raw material is an ortho-dihaloalkane (dihalooctane derivative) with the corresponding number of carbon atoms, which is vaporized at 30 Torr and 95 °C; (2) Two-stage temperature control: First stage (first elimination): Temperature 145±3℃, dwell time 7 seconds. Second stage (second elimination): Temperature 235±3℃, dwell time 5 seconds.

[0039] (3) Results Analysis: .

[0040] Example 3: Synthesis of compound (C12 product) where R1 = R2 = C5H11 in formula (I) Synthesize compounds having the structure of formula (I), wherein both alkyl groups are n-pentyl (total C12 carbons).

[0041] (1) The raw material is an ortho-dihaloalkanes with the corresponding number of carbon atoms (dihalododecane derivatives), which are vaporized at 18 Torr and 128 °C. (2) Two-stage temperature control: First stage (first elimination): Temperature 165±3℃, dwell time 7 seconds.

[0042] Second stage (second elimination): temperature 255±3℃, dwell time 8 seconds.

[0043] (3) Results Analysis: .

[0044] Example 4: Comparative Example – Pyrolysis Problems of High-Temperature Method Using the same raw materials and catalyst as in Example 1: The main difference is that the vaporization temperature in step 1 is increased to >250℃, and the temperature in the second stage is increased to 320℃.

[0045] Results: Although the conversion rate reached 85%, 15.3% of polymer (colloid) and 10.2% of cracking products (butane, hexene, etc.) were detected in the product. The selectivity of the target alkyne was only 68%, and the product purity was <80%, which could not meet the requirements for electronic grade.

[0046] Conclusion: Only under reduced pressure (<50 Torr) and medium temperature (220-280℃) conditions can a balance between high conversion rate and high selectivity be achieved.

[0047] Example 5: Comparative Example – The Selectivity and Yield Problem of Extended Time Using the same raw materials and catalyst as in Example 1, but increasing the second-stage high-temperature contact time by 10 seconds: Results: Although the conversion rate reached 98%, the selectivity decreased to about 70%, and about 25% of polymer (colloid) and 5% of pyrolysis products (butane, hexene, etc.) were detected in the product.

[0048] Conclusion: Only under conditions of <8 seconds can a balance between high conversion rate and high selectivity be achieved. Longer conditions will lead to significant activation of side reaction pathways, and increased molecular thermal motion will cause C-C bond breaking and free radical polymerization probability to rise simultaneously, significantly weakening the formation efficiency and purity stability of the target alkyne.

[0049] Example 6: Effect of catalyst base strength on elimination efficiency Comparison of catalysts with different base strengths (all loaded with 20 wt% active component, second-stage temperature fixed at 245℃, using the C9 product of Example 1 as a model): ; Conclusion: Only H>26 can effectively drive the elimination of vinyl halides at temperatures <260℃.

[0050] This invention solves the core challenge of internal alkyne synthesis by designing a two-step elimination chemical pathway for ortho-dihaloalkanes and combining it with decompression-confinement-temperature control engineering techniques. 1. Correctness of chemical principle: Using R1-CHX-CHX-R2 as the starting material ensures that R1-C≡C-R2 is generated after two eliminations; 2. Temperature controllability: The second-step elimination temperature is reduced to 220-280℃ by decompression, avoiding the cracking zone above 300℃; 3. Metal purity: Solvent-free, no transition metal catalysts, product metal ion content <100 ppb; 4. Continuous production: The gas-phase flow reactor supports 24 / 7 continuous operation, and the annual production capacity of a single unit can reach 3-5 tons.

[0051] Example 7: Reference Figure 1As shown, this invention also proposes the use of dialkyl acetylene compounds in semiconductor manufacturing as selective surface modification layers in advanced interconnect structures. Specifically, the dialkyl acetylene compounds hybridize with the d orbitals of the metal layer Cu or Co to form coordination bonds, but do not bond with the SiOx or SiNx thin film. Ultimately, a self-resisting layer is formed on the Cu or Co metal surface, thereby creating a certain steric hindrance and hydrophobicity to prevent subsequent film deposition. With heating, the coordination bonds in the self-resisting layer break and are removed, allowing subsequent metal electrodes to be directly deposited on the underlying metal, thereby reducing resistance.

[0052] It is suitable for the industrial production of electronic-grade dialkyl acetylene materials, meeting the purity requirements of precursor materials for semiconductor processes at 7nm and below.

[0053] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0054] The preferred embodiments of the invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for the reduced-pressure gas-phase synthesis of dialkylacetylene compounds, characterized in that, The dialkyl acetylene compound has the structure shown in formula (I): R1—C≡C—R2 (I); Includes the following steps: (1) Precursor decompression vaporization: The ortho-dihaloalkane feedstock having the structure of formula (II) is gasified and mixed with an inert carrier gas to obtain a mixed feedstock gas; R1—CHX—CHX—R2 (II); Where X is Cl, Br, or I; (2) Two-step continuous removal of hydrogen halides: The mixed feed gas obtained in step (1) is fed into a vacuum reactor loaded with a catalyst, and a two-step continuous elimination reaction is carried out to remove hydrogen halide under an absolute pressure of 10-50 Torr. (3) Separation and purification: The product-containing gas stream obtained in step (2) is subjected to reduced pressure condensation in a -30°C to -60°C cold trap to collect the crude product; the crude product is then subjected to short-path molecular distillation (10... -3 -10 -2 Torr) separates unreacted raw materials, hydrogen halide byproducts and target product to obtain purified product; (4) Inert atmosphere collection: The purified product obtained in step (3) was collected in a pre-cleaned sealed container under inert gas protection to obtain a high-purity dialkyl acetylene compound with a single metal ion impurity of <100 ppb.

2. The method for vacuum gas-phase synthesis of dialkyl acetylene compounds according to claim 1, characterized in that, In formulas (I) and (II), R1 and R2 are each selected from C1-C9 straight-chain or branched alkyl groups.

3. The method for vacuum gas-phase synthesis of dialkyl acetylene compounds according to claim 1, characterized in that, The raw material is selected from o-dihaloalkanes.

4. The method for vacuum gas-phase synthesis of dialkyl acetylene compounds according to claim 1, characterized in that, In step (1), the ortho-dihaloalkane feedstock is vaporized at 60-170°C under an absolute pressure of 10-50 Torr.

5. The method for vacuum gas-phase synthesis of dialkylacetylene compounds according to claim 1, characterized in that, In step (1), the inert carrier gas is argon or nitrogen, and the inert carrier gas has a molar ratio of 40:1 to 120:1 with the ortho-dihaloalkane raw material.

6. The method for vacuum gas-phase synthesis of dialkyl acetylene compounds according to claim 1, characterized in that, In step (2), the catalyst is selected from a composite system of metal carbonates, hydroxides, or alkoxides supported on a high specific surface area oxide support; the catalyst is Cs2CO3 / γ-Al2O3, KOH / Al2O3, or NaNH2 / molecular sieve, with an alkali loading of 10-30 wt% and a support specific surface area >250 m². 2 / g. (Its Hammett function (H0) is greater than 26;) According to claim 1, the method for vacuum gas-phase synthesis of dialkyl acetylene compounds is characterized in that the elimination step in step (2) includes: First step elimination: Temperature 140-180℃, residence time 5.0 seconds-10.0 seconds, to cause the first HX removal of compound (II) to generate vinyl halide intermediate R1-CH=CX-R2; The second elimination step involves a temperature of 220-280℃ and a residence time of 3.0-8.0 seconds. Under the influence of the ultra-alkaline sites on the catalyst surface, the vinyl halide intermediate undergoes a second de-HX reaction, generating a dialkyl acetylene of formula (I).

7. The method for vacuum gas-phase synthesis of dialkyl acetylene compounds according to claim 1, characterized in that, In step (3), the cold trap uses a liquid nitrogen / ethanol mixed bath (-50℃ to -60℃) to ensure efficient condensation of the product under reduced pressure and prevent blockage of the pipeline.

8. A dialkylacetylene compound, characterized in that, A compound having the structure shown in formula (I) prepared by a reduced-pressure gas-phase synthesis method of a dialkyl acetylene compound according to any one of claims 1-8, wherein R1 and R2 are C1-C9 alkyl groups, the product purity is > 99%, the content of single metal ion impurities is <100 ppb, and the residual halide ion is <5 ppb.

9. Use of a dialkylacetylene compound in semiconductor manufacturing.

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