Quaternary ammonium lye containing THEMAH, preparation method and application of quaternary ammonium lye

Abstract

The invention relates to a preparation method of quaternary ammonium alkali liquor containing tris-(2-hydroxyethyl) methylammonium hydroxide, which comprises the following steps: by adopting fluid reaction, enabling N-methyldiethanolamine and water as raw materials to react with ethylene oxide for 1-60 minutes at the temperature of-50 DEG C to 50 DEG C through a tubular reactor or a micro-channel reactor to obtain the quaternary ammonium alkali liquor containing THMAH. A tubular reactor or a micro-channel reactor used in the method is a reactor made of a non-metal material or a metal reactor sprayed with a non-metal material, the metal content and purity of N-methyldiethanolamine and water are controlled, and the prepared THMAH does not need to be further purified and can be directly used for a THMAH aqueous solution of the CMP post-cleaning composition, so that the preparation method is simple and convenient, and the cost is low. Through the combined action of the quaternary ammonium base and the organophosphorus chelating agent, complexing with residual pollutants on the surface of the wafer is realized, the water solubility is improved, and the residual pollutants can be removed more easily.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of quaternary ammonium base containing tri-(2-hydroxyethyl) methyl ammonium hydroxide and its preparation method, chemical mechanical polishing post cleaning composition and the cleaning method of semiconductor device substrate. BACKGROUND

[0002] Aqueous quaternary ammonium base compound is commonly used in the composition of CMP post cleaning composition, such as tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, choline hydroxide, tri(2-hydroxyethyl) methyl ammonium hydroxide (THEMAH) and the like, which can significantly improve the efficiency of CMP post cleaning process, and is widely used in various process alkaline cleaning solution.

[0003] In addition, quaternary ammonium base is also widely used in etching and stripping process preparation, and is an indispensable class of compounds in the field of semiconductors. Among them, tetramethylammonium hydroxide (TMAH) has been reported many times in the use of semiconductor preparation, and is widely used in existing process, but its toxicity is huge, and contact with skin can cause damage to nervous system, which seriously endangers personal safety.

[0004] In the report of CN116496853A, tri(2-hydroxyethyl) methyl ammonium hydroxide (THEMAH) can replace tetramethylammonium hydroxide (TMAH) as quaternary ammonium base component in alkaline cleaning solution, and can achieve the expected cleaning capacity.

[0005] Currently marketed THEMAH is mainly imported, and has not been localized. In US6340559B1, tri-(2-hydroxyethyl) methyl ammonium hydroxide aqueous solution is synthesized by one-pot method in huntsman reactor through N-methyldiethanolamine and ethylene oxide in the presence of water. This method needs to slowly add a large amount of ethylene oxide gas, and the reaction time is long, which has great limitation to reaction volume, cannot mass production, and the system has the risk of too high pressure, which will cause serious safety hazard; the reaction process will release heat, the system needs to be controlled at below 20℃, the condition is harsh, and there is the risk of local temperature too high, which is easy to explode under high pressure; in addition, it is carried out in the reactor, the material will contact the thermometer, stirrer, reactor, metal pipeline and other devices, and the synthesized THEMAH product needs to be further purified before it can be applied to semiconductor cleaning chemicals. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application provides a kind of quaternary ammonium base containing tri-(2-hydroxyethyl) methyl ammonium hydroxide and its preparation method, and the total metal content of electronic grade quaternary ammonium base in the present application is less than 35 ppb, which does not need to be purified and can be directly used in CMP post cleaning composition.

[0007] To achieve the above object, the first aspect of the present application provides a solution of quaternary ammonium base containing tri-(2-hydroxyethyl)methylammonium hydroxide, which is prepared by fluid reaction through a tubular reactor or a micro-channel reactor, using N-methyldiethanolamine and water as raw materials, and reacting with ethylene oxide at a temperature of -50℃ to 50℃ for 1-60 minutes.

[0008] The tubular reactor or micro-channel reactor mentioned above can be a reactor made of non-metallic material or a metal reactor sprayed with non-metallic material.

[0009] Further, the total metal content of the raw materials N-methyldiethanolamine and ethylene oxide is <50 ppb, and the raw material water is electronic grade pure water (single metal <1 ppb).

[0010] Preferably, the total metal content of the quaternary ammonium base solution is <35 ppb.

[0011] The second aspect of the present application provides a preparation method of a solution of quaternary ammonium base containing tri-(2-hydroxyethyl)methylammonium hydroxide, which is prepared by fluid reaction through a tubular reactor or a micro-channel reactor, using N-methyldiethanolamine and water as raw materials, and reacting with ethylene oxide at a temperature of -50℃ to 50℃ for 1-60 minutes to obtain a solution of quaternary ammonium base containing tri-(2-hydroxyethyl)methylammonium hydroxide.

[0012] Further, the tubular reactor or micro-channel reactor is a reactor made of non-metallic material or a metal reactor sprayed with non-metallic material.

[0013] Further, the total metal content of the N-methyldiethanolamine and ethylene oxide is <50 ppb; and the raw material water is electronic grade pure water (single metal <1 ppb).

[0014] The preparation method of the solution of quaternary ammonium base containing tri-(2-hydroxyethyl)methylammonium hydroxide specifically includes the following steps:

[0015] Step I: After mixing N-methyldiethanolamine and water uniformly in a clean container, one end is connected with a nitrogen pipeline for replacing the atmosphere in the pipeline before and after feeding, one end is connected with the feed inlet of the tubular reactor or micro-channel reactor, and one end is sealed for pressure relief when the pipeline is blocked;

[0016] Step II: The ethylene oxide feed inlet is connected with a three-way joint through a plastic pipeline, the other two ends of the three-way joint are connected with a nitrogen pipeline and the feed inlet of the tubular reactor or micro-channel reactor, respectively, and the nitrogen pipeline is used for replacing the atmosphere in the pipeline before and after feeding;

[0017] Step III: The atmosphere of the entire device from the storage bottle to the product collection bottle is replaced with nitrogen for 6-60 minutes to replace the atmosphere in the system with nitrogen;

[0018] Step IV: connect the tubular reactor or micro-channel reactor and integrated machine to power supply, control the temperature of the pipeline to be -50℃-50℃; after the temperature is stable, pass N-methyldiethanolamine aqueous solution and ethylene oxide gas into the pipeline at a fixed flow rate, and the raw materials are mixed and reacted in the pipeline of the reactor for 1-60 minutes;

[0019] Step V: after the product flows out from the outlet of the tubular reactor or micro-channel reactor, the pipeline is flushed with nitrogen and the product is bubbled for 6-60 minutes, and finally a quaternary ammonium base solution containing N-methyldiethanolamine and tris(2-hydroxyethyl)methylammonium hydroxide (THEMAH) is collected.

[0020] Further, the reaction temperature of the N-methyldiethanolamine aqueous solution and ethylene oxide gas is preferably -30℃-40℃.

[0021] The molar ratio of N-methyldiethanolamine to ethylene oxide is 1:0.8-1.2; the mass ratio of N-methyldiethanolamine to ultrapure water is 1:0.1-3;

[0022] And / or, the feeding flow rate of the N-methyldiethanolamine aqueous solution is 0.077-0.926 kg / min; the feeding flow rate of the ethylene oxide is 0.019-0.228 kg / min.

[0023] The third aspect of the present application provides an application of a quaternary ammonium base solution containing tris(2-hydroxyethyl)methylammonium hydroxide. The quaternary ammonium base solution containing tris(2-hydroxyethyl)methylammonium hydroxide is used as a cleaning agent, a chemical polishing agent, a solvent, a complexing agent, a developing agent, a surfactant, an electrolyte, an analytical reagent, etc., and is preferably applied to semiconductor formula cleaning, etching or stripping.

[0024] The fourth aspect of the present application provides an application of a quaternary ammonium base solution in a post-chemical mechanical polishing cleaning composition, which comprises the following components: a pH adjuster 0.1wt%-10wt%, a quaternary ammonium base 1wt%-10wt%, a wetting agent 0.005wt%-1wt%, and an organic phosphine chelating agent 0.01wt%-5wt%; the quaternary ammonium base solution is the product directly prepared by the preparation method of any one of the above.

[0025] The pH is between 9 and 13;

[0026] The amount of the quaternary ammonium base solution is preferably 2%-6% of the total weight of the cleaning composition;

[0027] And / or, the amount of the wetting agent is preferably 0.01%-1% of the total weight of the cleaning composition;

[0028] Preferably, the organic phosphine chelating agent is used in an amount of 0.1 to 2% by weight of the cleaning composition.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] 1、The present application adopts fluid reaction to prepare quaternary ammonium base solution containing tri-(2-hydroxyethyl) methyl ammonium hydroxide through a tubular reactor or a micro-channel reactor, which is superior to one-pot synthesis using a huntsman reaction kettle, and there is no risk of excessively high pressure, the device has multiple gas outlets, and the size of the system pressure can be adjusted at any time; the flow rate of the feed inlet can be controlled to control the time of the raw material mixture after uniform mixing in the micro-channel reactor pipeline, and the controllability is stronger; the reaction efficiency is higher, and the production capacity can be enlarged by prolonging the pipeline length and diameter in the micro-channel reactor; the temperature of the pipeline in the tubular reactor or the micro-channel reactor is directly controlled, and the risk of excessively high local temperature is avoided;

[0031] 2、The tubular reactor or the micro-channel reactor in the present application adopts a non-metal material (silicon carbide, graphite, fluoroplastic, glass, etc.) or a metal sprayed with a non-metal material, and the remaining material-contacting accessories and pipelines are clean plastic (PFA, PVDF, PTFE, etc.) or metal parts sprayed with a non-metal material, so that metal is not introduced during use, and the metal content and purity of N-methyl diethanolamine and ultrapure water are controlled; in the absence of pollution of other devices and materials, the prepared THEMAH does not need to be further purified and can be directly used in the semiconductor industry, that is, the THEMAH aqueous solution for the post-CMP cleaning composition can be directly used, meeting the requirements of the semiconductor industry for metal ions and purity of raw materials;

[0032] 3、The post-CMP cleaning composition involved in the present application, through the combined action of quaternary ammonium base and organic phosphorus chelating agent, is used for post-cleaning of copper CMP, is combined with residual pollutants on the wafer surface, improves the water solubility, so that it is more easily removed, and no defects and damage are caused. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0034] Figure 1 It is a flowchart of the specific steps in the preparation method of the quaternary ammonium base solution in the embodiments of the present application. DETAILED DESCRIPTION

[0035] Embodiments of the present application will be described in detail below with reference to examples, but those skilled in the art will appreciate that the examples below are intended to be illustrative only and should not be viewed as limiting the scope of the present application. Where specific conditions are not indicated in the examples, they were carried out under conventional conditions or as recommended by the manufacturer. Where the manufacturer of reagents or instruments is not indicated, the conventional products available commercially were used.

[0036] As used herein in connection with the present application, the term "semiconductor device" is intended to encompass microelectronic device wafers used to form integrated circuits, including substrates such as silicon, regions on the substrates are patterned for the deposition of a variety of different materials having insulative, conductive, and / or semiconductive properties.

[0037] As used herein in connection with the present application, the term "residues and contaminants" is intended to refer to small particles, extraneous matter, and any type of debris that is formed during any or all of the typical microelectronic device processing steps (including plasma etching, ashing, chemical mechanical polishing, wet etching, and post-chemical mechanical polishing cleaning, and combinations thereof) that remain on the wafer surface, the size of the particles can vary from a few microns in size down to the very small particle range; wherein the residues and contaminants typically include all classes of particles that result from the selection of chemicals used in the chemical mechanical polishing slurry, these particles can include reaction by-products of the polishing slurry, chemicals and reaction by-products from the wet etching, and other materials that result from by-products of various device processing formation processes such as plasma etching or plasma ashing treatments.

[0038] As used herein in connection with the present application, the term "residues and contaminants" is intended to refer to small particles, extraneous matter, and any type of debris that is formed during any or all of the typical microelectronic device processing steps (including plasma etching, ashing, chemical mechanical polishing, wet etching, and post-chemical mechanical polishing cleaning, and combinations thereof) that remain on the wafer surface, the size of the particles can vary from a few microns in size down to the very small particle range; wherein the residues and contaminants typically include all classes of particles that result from the selection of chemicals used in the chemical mechanical polishing slurry, these particles can include reaction by-products of the polishing slurry, chemicals and reaction by-products from the wet etching, and other materials that result from by-products of various device processing formation processes such as plasma etching or plasma ashing treatments.

[0039] As used herein in connection with the present application, the term "low dielectric constant material" corresponds to any material used as a node material in layered microelectronic devices, wherein the material has a dielectric constant less than 3.5, selected materials include but are not limited to, silicon-containing organic polymers, silicon-containing organic / inorganic hybrid materials, organosilicate glass (OSG), TEOS, fluorinated silicate glass (FSG), silicon dioxide, and carbon-doped oxide (CDO) glass.

[0040] <Quaternary ammonium base solution containing tri-(2-hydroxyethyl)methylammonium hydroxide>

[0041] The present application provides a kind of quaternary ammonium base solution containing tri-(2-hydroxyethyl) methyl ammonium hydroxide, which is prepared by fluid reaction, through tubular reactor or microchannel reactor, using N-methyldiethanolamine and water as raw materials, reacting with ethylene oxide at temperature-50℃-50℃ for 1-60 minutes to obtain.

[0042] In the embodiments of the present application, the tubular reactor or microchannel reactor is preferably a reactor made of non-metallic material (silicon carbide, graphite, fluoroplastic, glass, etc.) or a metal reactor coated with non-metallic material, and other containers or pipelines in contact with materials are made of clean plastic (PFA, PVDF, PTFE, etc.) or metal parts coated with non-metallic material, for example, the tubular reactor or microchannel reactor is a reactor made of silicon carbide, and other containers or pipelines in contact with materials are made of PVDF material; in another embodiment, no catalyst is used, and high-purity, low-metal-impurity reaction raw materials are used, such as electronic-grade N-methyldiethanolamine, ethylene oxide and electronic-grade ultrapure water, wherein the total metal content of the electronic-grade N-methyldiethanolamine and ethylene oxide is <50ppb, and electronic-grade THEMAH quaternary ammonium base solution can be prepared.

[0043] The electronic-grade THEMAH quaternary ammonium base solution of the present application has a total metal content of <35ppb, and does not need further purification, and can be directly used in the semiconductor industry, i.e., the THEMAH aqueous solution can be directly used in the post-CMP cleaning composition, meeting the requirements of the semiconductor industry for metal ions and purity of raw materials.

[0044] <Method for preparing quaternary ammonium base solution containing tri-(2-hydroxyethyl) methyl ammonium hydroxide>

[0045] The present application provides a method for preparing a quaternary ammonium base solution containing tri-(2-hydroxyethyl) methyl ammonium hydroxide (THEMAH), which is prepared by fluid reaction, through tubular reactor or microchannel reactor, using N-methyldiethanolamine and water as raw materials, reacting with ethylene oxide at-50℃-50℃ for 1-60 minutes to obtain THEMAH-containing quaternary ammonium base aqueous solution.

[0046] The method for preparing quaternary ammonium base solution containing tri-(2-hydroxyethyl) methyl ammonium hydroxide by tubular reactor or microchannel reactor is superior to one-pot synthesis using huntsman reactor, does not need to be pressurized, and there is no risk of excessive pressure, the device has multiple gas outlets, and the size of the system pressure can be adjusted at any time; the flow rate of the feed inlet can be controlled to control the time the raw material mixture stays in the microchannel reactor pipeline, and the controllability is stronger; the reaction can be completed within 1-60 minutes, the efficiency is higher, and the capacity can be enlarged by extending the length and diameter of the pipeline in the microchannel reactor; and the temperature of the pipeline in the tubular reactor or microchannel reactor is directly controlled, avoiding the risk of excessive local temperature.

[0047] Specifically comprising the following steps:

[0048] Step I: After mixing the raw material N-methyldiethanolamine and water uniformly in a clean container to obtain an N-methyldiethanolamine aqueous solution, one end is connected with a nitrogen pipeline for replacing the atmosphere in the pipeline before and after feeding, one end is connected with the feeding port of a tubular reactor or a microchannel reactor, and one end is sealed for pressure relief when the pipeline is blocked;

[0049] Step II: The epoxy ethane feeding port is connected with a three-way joint through a plastic pipeline, the other two ends of the three-way joint are connected with a nitrogen pipeline and the feeding port of the tubular reactor or the microchannel reactor, and the nitrogen pipeline is used for replacing the atmosphere in the pipeline before and after feeding;

[0050] Step III: The atmosphere of the entire device from the storage bottle to the product collection bottle is replaced with nitrogen for 6-60 minutes to replace the atmosphere in the system with nitrogen;

[0051] Step IV: The tubular reactor or the microchannel reactor and the all-in-one machine are connected with power, the pipeline temperature is controlled to be-50℃-50℃, after the temperature is stable, N-methyldiethanolamine aqueous solution and epoxy ethane gas are fed at a fixed flow rate, and the temperature is controlled to be within ±2℃, the raw materials are mixed and reacted in the reactor pipeline for 1-60 minutes;

[0052] Step V: After the product flows out from the discharge port of the tubular reactor or the microchannel reactor, the pipeline is flushed with nitrogen and the product is bubbled for 6-60 minutes, and finally a quaternary ammonium base solution containing N-methyldiethanolamine and tris(2-hydroxyethyl)methylammonium hydroxide (THEMAH) is collected.

[0053] In the embodiment of the application, the reaction temperature is-50℃-50℃, and is further preferably-30℃-40℃. The temperature of the microchannel reactor pipeline is controlled by the all-in-one machine, and as the temperature rises, the reaction rate gradually increases. When the temperature is lower than 50℃, the reaction of N-methyldiethanolamine and epoxy ethane will only generate THEMAH, but when the temperature is lower than-30℃, the reaction rate will obviously decrease; when the temperature is higher than 50℃, although the reaction rate still increases, the reaction of N-methyldiethanolamine and epoxy ethane will generate by-products in addition to THEMAH.

[0054] In the embodiment of the application, the molar ratio of N-methyldiethanolamine to epoxy ethane is 1:0.8-1.2; and the mass ratio of the N-methyldiethanolamine to ultrapure water is 1:0.1-3;

[0055] In the embodiment of the application, the feeding flow rate of the N-methyldiethanolamine aqueous solution is preferably 0.077-0.926 kg / min; and the feeding flow rate of the epoxy ethane is 0.019-0.228 kg / min.

[0056] Finally, the additive is added at the time of feeding or after discharging, and is stirred uniformly; the additive is selected from one or more of phenothiazine, hydroquinone, 4-methoxyphenol, 2-tert-butyl hydroquinone, 2,5-di-tert-butyl hydroquinone, 2,6-di-tert-butyl-4-methylphenol, ethylenediamine, hydroxyethylethylenediamine (AEEA), diethylhydroxylamine. The additive can delay the product from oxidizing and discoloring. Different antioxidants can produce different antioxidant effects. Without the antioxidant, the product is prone to discoloring and yellowing during storage, and the addition of the antioxidant can prolong the time during which the product does not discolor during storage. Different antioxidants and addition amounts can affect the time during which the product does not discolor during storage.

[0057] The above-mentioned tube reactor or micro-channel reactor is preferably a reactor made of non-metallic material (silicon carbide, graphite, fluoroplastic, glass, etc.) or a metal reactor sprayed with non-metallic material, and other containers or pipelines in contact with the material are preferably clean plastic (PFA, PVDF, PTFE, etc.) or metal parts sprayed with non-metallic material, so as to ensure that no metal impurities are introduced during the preparation process.

[0058] In addition, the present application further uses reaction raw materials with high purity and low metal impurities, such as electronic-grade N-methyldiethanolamine, ethylene oxide and electronic-grade ultrapure water, wherein the total metal content of the electronic-grade N-methyldiethanolamine and ethylene oxide is <50 ppb, so that the electronic-grade THEMAH quaternary ammonium lye can be prepared.

[0059] <Application of quaternary ammonium lye containing tris-(2-hydroxyethyl)methylammonium hydroxide>

[0060] The quaternary ammonium lye containing tris-(2-hydroxyethyl)methylammonium hydroxide provided by the present application can be used as a cleaning agent, a chemical polishing agent, a solvent, a complexing agent, a developing agent, a surfactant, an electrolyte, an analytical reagent, etc., and is preferably applied in semiconductor devices, such as semiconductor formula cleaning, etching or stripping.

[0061] In the embodiments of the present application, the electronic-grade quaternary ammonium lye is preferably applied in a post-chemical mechanical polishing cleaning composition, and the post-chemical mechanical polishing cleaning composition comprises the following components: a pH regulator 0.1wt%-10wt%, a quaternary ammonium lye 1wt%-10wt%, a wetting agent 0.005wt%-1wt%, and an organic phosphine chelating agent 0.01wt%-5wt%; the electronic-grade quaternary ammonium lye is the product directly obtained by the preparation method of the quaternary ammonium lye in any of the above-mentioned schemes.

[0062] The pH of the post-chemical mechanical polishing cleaning composition is between 9 and 13, and is preferably between 10 and 12.

[0063] The pH adjusting agent is selected from the group consisting of ammonium hydroxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, monoethanolamine, diethanolamine, triethanolamine, methylethanolamine, methyldiethanolamine, tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, tetraethylammonium hydroxide, tetramethylammonium hydroxide, ethyltrimethylammonium hydroxide, diethyldimethylammonium hydroxide, dimethyldipropylammonium hydroxide, benzyltrimethylammonium hydroxide, tris(2-hydroxyethyl)methylammonium hydroxide, choline hydroxide, and any combination thereof. In one or more embodiments, the pH adjusting agent is an organic base. Without being bound by theory, it is believed that organic base pH adjusting agents can provide better cleaning efficiency while effectively avoiding metal ion (e.g., Na or K) contamination when compared to inorganic pH adjusting agents.

[0064] The pH adjusting agent is used in an amount of 0.1% to 10%, preferably 1% to 6%, by weight of the total cleaning composition.

[0065] The quaternary ammonium base is used in an amount of 1% to 10%, preferably 2% to 6%, by weight of the total cleaning composition.

[0066] The wetting agent is selected from one or more of octadecyl amine polyoxyethylene ether, betaine, polyethylene ether lauric acid, hydroxyethyl cellulose, and derivatives thereof.

[0067] The wetting agent is used in an amount of 0.005% to 1%, preferably 0.01% to 1%, by weight of the total cleaning composition.

[0068] The organic phosphine chelating agent is selected from one or more of 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA), amino-tris(methylene-phosphonic acid) (ATMP), ethylenediamine tetra(methylene-phosphonic acid) (EDTMPA), hexamethylene diamine tetra(methylene-phosphonic acid) (HDTMPA), diethylenetriamine penta(methylene-phosphonic acid) (DTPMP), poly(amino polyether methylene-phosphonic acid) (PAPEMP), hydroxyethylidene diphosphonic acid (HEDP), polyol phosphates (PAPE), 2-hydroxyphosphonooxyacetic acid (HPAA), bis-1,6-hexylenetriamine penta(methylene-phosphonic acid) (BHMTPMPA), or derivatives thereof.

[0069] The organic phosphine chelating agent is used in an amount of 0.01% to 5%, preferably 0.1% to 2%, by weight of the total cleaning composition after chemical mechanical polishing.

[0070] In the chemical mechanical polishing after cleaning solution composition of the present application, as other additives, water can be included, which can control the ease of pH adjustment, handling, safety, reactivity with the polished surface, and the like.

[0071] The chemical mechanical polishing after cleaning composition provided by the present application is mainly used for cleaning after the copper CMP process. The coaction of the quaternary amine base and the organic phosphine chelating agent further enhances the removal ability of the pollutants, and can form strong interaction with Cu 2+ to achieve the effect of removing residual Cu 2+ .

[0072] <Method for cleaning semiconductor device substrate>

[0073] The method for cleaning semiconductor device substrate in the present application can remove the undesirable residues and pollutants from the surface of the semiconductor device substrate by any suitable method or way using the alkaline chemical mechanical polishing after cleaning composition described in the present application. For example, the chemical mechanical polishing after cleaning composition can be sprayed onto the clean device surface, or the semiconductor device substrate can be immersed in a certain volume of the chemical mechanical polishing after cleaning composition at room temperature for 1 minute to 5 minutes; then the semiconductor device substrate can be optionally washed with deionized water to remove at least 90% of the residues and pollutants.

[0074] Before contacting the surface of the semiconductor device, the alkaline chemical mechanical polishing after cleaning composition in the present application can be further diluted with deionized water. Any suitable mixing method can be selected. For example, the mixing method is as follows: mixing with deionized water according to the set mixing ratio, storing in a storage tank, circulating the storage tank in a continuous manner, and simultaneously introducing wet nitrogen for protection to prevent the product from being prepared and the concentration from fluctuating; or respectively drawing from two pipelines of the cleaning composition and deionized water, controlling the flow rate of the composition and deionized water according to the set mixing ratio, combining into the same pipeline to form a two-fluid, thereby obtaining the mixing effect; the set mixing ratio of the chemical mechanical polishing after cleaning composition and deionized water in the present application is between 1:5 and 1:30.

[0075] The technical solutions in the specific embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application.

[0076] The raw materials involved in the examples and comparative examples: N-methyldiethanolamine is a commercially available electronic grade product or a commercially available industrial product purified by rectification to meet the requirements of electronic grade, and ethylene oxide is a commercially available bulk gas and is filtered through a gas filter, wherein the total metal content of N-methyldiethanolamine and ethylene oxide is <50 ppb; ultrapure water is electronic grade pure water (single metal <1 ppb) meeting the conditions.

[0077] Preparation of quaternary ammonium lye containing tri(2-hydroxyethyl)methylammonium hydroxide (THEMAH)

[0078] Synthesis Example 1

[0079] N-methyldiethanolamine (2.87 kg, 24.1 mol) was added to a clean container, 1.76 kg of water was added and stirred uniformly, and was connected to the nitrogen pipeline and the micro-channel reactor feed port through a plastic pipeline, respectively. Ethylene oxide was connected to the nitrogen pipeline and the micro-channel reactor feed port through a three-way valve, respectively. Nitrogen was introduced into the feed end of the device, and nitrogen was discharged from the discharge end, which lasted for 30 minutes, so that the atmosphere in the system was completely replaced by nitrogen. The temperature of the micro-channel reactor pipeline was controlled at 20±2℃, N-methyldiethanolamine aqueous solution was introduced at a flow rate of 0.463 kg / min, and ethylene oxide gas was introduced at a flow rate of 0.114 kg / min (1.14 kg, 25.9 mol), so as to control the reaction of the raw materials in the micro-channel reactor pipeline for 5 minutes after mixing.

[0080] The product flowed from the micro-channel reactor into the liquid collection bottle at the tail, 30 g of hydroxyethyl ethylenediamine was added in advance in the collection bottle, and the collection bottle was connected to a water pool for air sealing. After the raw materials were completely introduced into the feed port, nitrogen was continuously introduced into the system for 30 minutes to empty the materials in the micro-channel reactor and the residual ethylene oxide gas in the system. The obtained product was a colorless aqueous solution, which contained 48.3% of THEMAH and 11.9% of N-methyldiethanolamine by nuclear magnetic hydrogen spectrum, the pH was 12.8, and the total metal content of the colorless aqueous solution was <35 ppb by ICP.

[0081] Synthesis Example 2

[0082] The method for preparing THEMAH-containing quaternary ammonium lye according to synthesis example 1, the difference is that the temperature of the micro-channel reactor pipeline is controlled at 40±2℃. The obtained product is a colorless aqueous solution, which contains 50.2% of THEMAH and 11.6% of N-methyldiethanolamine by nuclear magnetic hydrogen spectrum, the pH is 13.2, and the total metal content of the colorless aqueous solution is <35 ppb by ICP.

[0083] Synthesis Example 3

[0084] The method for preparing THEMAH-containing quaternary ammonium base solution according to Synthesis Example 1 was used, except that the microchannel reactor pipe temperature was controlled at 0±2°C, and the N-methyldiethanolamine aqueous solution was passed at a flow rate of 0.231 kg / min and the ethylene oxide gas was passed at a flow rate of 0.057 kg / min, so as to control the reaction of the raw materials after mixing in the microchannel reactor pipe for 30 minutes. The product obtained was a colorless aqueous solution, which contained 46.3% THEMAH and 12.5% N-methyldiethanolamine by 1H NMR, had a pH of 12.3, and had a total metal content of <35 ppb in the colorless aqueous solution by ICP.

[0085] Synthesis Example 4

[0086] The method for preparing THEMAH-containing quaternary ammonium base solution according to Synthesis Example 1 was used, except that the microchannel reactor pipe temperature was controlled at -30±2°C. The N-methyldiethanolamine aqueous solution was passed at a flow rate of 0.423 kg / min and the ethylene oxide gas was passed at a flow rate of 0.114 kg / min, so as to control the reaction of the raw materials after mixing in the microchannel reactor pipe for 10 minutes. The product obtained was a colorless aqueous solution, which contained 45.0% THEMAH and 13.3% N-methyldiethanolamine by 1H NMR, had a pH of 12.1, and had a total metal content of <35 ppb in the colorless aqueous solution by ICP.

[0087] Synthesis Example 5

[0088] The method for preparing THEMAH-containing quaternary ammonium base solution according to Synthesis Example 1 was used, except that the microchannel reactor pipe temperature was controlled at -30±2°C, and the N-methyldiethanolamine aqueous solution was passed at a flow rate of 0.423 kg / min and the ethylene oxide gas was passed at a flow rate of 0.114 kg / min, so as to control the reaction of the raw materials after mixing in the microchannel reactor pipe for 50 minutes. The product obtained was a colorless aqueous solution, which contained 45.8% THEMAH and 13.0% N-methyldiethanolamine by 1H NMR, had a pH of 12.0, and had a total metal content of <35 ppb in the colorless aqueous solution by ICP.

[0089] Synthesis Example 6

[0090] The process for preparing THEMAH-containing quaternary ammonium base solution according to Synthesis Example 1 was followed, except that N-methyldiethanolamine (3.71 kg, 31.0 mol) was stirred with 1.76 kg of water, the N-methyldiethanolamine aqueous solution was passed at a flow rate of 0.926 kg / min, and the ethylene oxide gas was passed at a flow rate of 0.228 kg / min, to control the reaction in the microchannel reactor line for 10 minutes after the raw materials were mixed. The resulting product was a colorless aqueous solution containing 46.4% of THEMAH and 12.6% of N-methyldiethanolamine by 1H NMR, pH 12.1, and the total metal content of the colorless aqueous solution was < 35 ppb by ICP.

[0091] Synthesis Example 7

[0092] The process for preparing THEMAH-containing quaternary ammonium base solution according to Synthesis Example 1 was followed, except that N-methyldiethanolamine (3.71 kg, 31.0 mol) was stirred with 1.76 kg of water, the N-methyldiethanolamine aqueous solution was passed at a flow rate of 0.926 kg / min, and the ethylene oxide gas was passed at a flow rate of 0.228 kg / min, to control the reaction in the microchannel reactor line for 10 minutes after the raw materials were mixed. The resulting product was a colorless aqueous solution containing 46.4% of THEMAH and 12.6% of N-methyldiethanolamine by 1H NMR, pH 12.1, and the total metal content of the colorless aqueous solution was < 35 ppb by ICP.

[0093] Synthesis Example 8

[0094] The process for preparing THEMAH-containing quaternary ammonium base solution according to Synthesis Example 1 was followed, except that the ethylene oxide gas was passed at a flow rate of 0.13 kg / min (1.28 kg, 29.0 mol), to control the reaction in the microchannel reactor line for 5 minutes after the raw materials were mixed. The resulting product was a colorless aqueous solution containing 47.1% of THEMAH and 11.8% of N-methyldiethanolamine by 1H NMR, pH 12.15, and the total metal content of the aqueous solution was < 35 ppb by ICP.

[0095] Synthesis Example 9

[0096] The process for preparing THEMAH-containing quaternary ammonium base solution according to Synthesis Example 1 was followed, except that the temperature of the microchannel reactor line was controlled at 50 ± 2°C. The resulting product was a colorless aqueous solution containing 55.0% of THEMAH and 9.8% of N-methyldiethanolamine by 1H NMR, pH 13.8, and the total metal content of the colorless aqueous solution was < 35 ppb by ICP.

[0097] Synthesis Example 10

[0098] The method for preparing THEMAH-containing quaternary ammonium base solution according to Synthesis Example 1 was used, except that the microchannel reactor tube temperature was controlled at -50 ± 2°C, and the reaction in the microchannel reactor tube was controlled for 60 minutes after the raw materials were mixed. The product obtained was a colorless aqueous solution containing 40.5% THEMAH and 18.0% N-methyldiethanolamine by 1H NMR, and the pH was 11.7. The total metal content of the colorless aqueous solution was < 35 ppb by ICP.

[0099] Synthesis Example 11

[0100] The method for preparing THEMAH-containing quaternary ammonium base solution according to Synthesis Example 1 was used, except that the N-methyldiethanolamine aqueous solution was passed at a flow rate of 0.950 kg / min and the ethylene oxide gas (1.14 kg, 25.9 mol) was passed at a flow rate of 0.250 kg / min, so as to control the reaction in the microchannel reactor tube for 1 minute after the raw materials were mixed. The product obtained was a colorless aqueous solution containing 21.0% THEMAH and 37.5% N-methyldiethanolamine by 1H NMR, and the pH was 11.0. The total metal content of the colorless aqueous solution was < 35 ppb by ICP.

[0101] Synthesis Example 12

[0102] The method for preparing THEMAH-containing quaternary ammonium base solution according to Synthesis Example 1 was used, except that the N-methyldiethanolamine aqueous solution was passed at a flow rate of 0.230 kg / min and the ethylene oxide gas (1.14 kg, 25.9 mol) was passed at a flow rate of 0.050 kg / min, so as to control the reaction in the microchannel reactor tube for 20 minutes after the raw materials were mixed. The product obtained was a colorless aqueous solution containing 53.0% THEMAH and 3.0% N-methyldiethanolamine by 1H NMR, and the pH was 13.1. The total metal content of the colorless aqueous solution was < 35 ppb by ICP.

[0103] Synthesis Example 13

[0104] N-methyldiethanolamine (287 kg, 2410 mol) was charged into a clean vessel, and 287 kg of water was added and stirred to homogeneity, and connected to the nitrogen line and the feed inlet of the tube reactor via plastic tubing. Ethylene oxide was connected to the three-way valve and the nitrogen line and the feed inlet of the tube reactor. Nitrogen was passed through the feed end of the apparatus and out the discharge end for 30 minutes to replace the atmosphere in the system with nitrogen. The temperature of the tube reactor was controlled at 20 ± 5 °C, and the N-methyldiethanolamine solution was passed at a rate of 4.63 kg / min and ethylene oxide gas (114 kg, 2590 mol) was passed at a rate of 1.14 kg / min to control the reaction of the feed mixture in the tube reactor for 50 minutes. The product flowed from the microchannel reactor into a collection bottle at the end of the tube, which contained 3.5 kg of hydroxyethylethylenediamine added in advance, and the collection bottle was connected to a water bath to trap the gas. After the feed was completely introduced into the feed inlet, nitrogen was continuously passed through the system for 30 minutes to empty the microchannel reactor and the system of the remaining ethylene oxide gas. The product was a colorless aqueous solution, which contained 49.0% THEMAH and 12.3% N-methyldiethanolamine by 1H NMR, and the pH was 13.0. The total metal content of the aqueous solution was < 35 ppb by ICP.

[0105] Comparative Example 1

[0106] The method for preparing a THEMAH-containing quaternary ammonium base solution according to Synthesis Example 1 was used, except that the temperature of the microchannel reactor was controlled at 60 ± 2 °C, and the N-methyldiethanolamine solution was passed at a rate of 0.926 kg / min and ethylene oxide gas was passed at a rate of 0.228 kg / min to control the reaction of the feed mixture in the microchannel reactor for 5 minutes. The product was a yellow aqueous solution, which contained 10% THEMAH and 58% byproducts (a variety of chemicals in the same series as the product) by 1H NMR. The pH was 12.1, and the total metal content of the aqueous solution was < 35 ppb by ICP.

[0107] Comparative Example 2

[0108] The method for preparing a THEMAH-containing quaternary ammonium base solution according to Synthesis Example 1 was used, except that the temperature of the microchannel reactor was controlled at -70 ± 2 °C, and the N-methyldiethanolamine solution was passed at a rate of 0.077 kg / min and ethylene oxide gas was passed at a rate of 0.019 kg / min to control the reaction of the feed mixture in the microchannel reactor for 70 minutes. The product was a colorless aqueous solution, which contained 1% THEMAH and 55% N-methyldiethanolamine by 1H NMR, and the pH was 10.5. The total metal content of the aqueous solution was < 50 ppb by ICP.

[0109] The commercially available THEMAH-containing quaternary ammonium base solution is generally a 45-53 wt% aqueous solution of THEMAH, containing a portion of MDEA (methyl diethanol amine) and a stabilizer. In the semiconductor manufacturing process, the THEMAH-containing quaternary ammonium base solution of this concentration is generally used directly to prepare cleaning solutions and the like. Further, the commercially available THEMAH-containing quaternary ammonium base solution contains 11.5-14 wt% of methyl diethanol amine, and in order to ensure the subsequent use of the quaternary ammonium base solution composition product, it is necessary to meet the specifications for the content of alkaline substances in the cleaning solution. Therefore, the THEMAH-containing quaternary ammonium base solution prepared in Synthesis Examples 1-8 and Synthesis Example 13 containing tris(2-hydroxyethyl)methylammonium hydroxide (THEMAH) was selected as the quaternary ammonium base component of the post-CMP cleaning composition.

[0110] Preparation of post-chemical mechanical polishing cleaning compositions

[0111] Preparation method: The components were simply mixed according to the formulations (specific components and corresponding specific contents) of each of the examples and comparative examples in Table 1, and diluted 6 times for use.

[0112] Table 1

[0113]

[0114] The performance of the post-CMP cleaning composition was evaluated by verifying the chemical mechanical polishing application, and the test conditions were as follows:

[0115] The test machine was an AMAT Refelxion (Modify 5 Zone).

[0116] The polishing pad was a DH3000 series polishing pad of DINGLONG.

[0117] The polishing solution was DB2801 (slurry (g):DIW (g):31.16% H2O2 (g)=76.88:0:1) at a flow rate of 200 mL / min.

[0118] The conditioning disk was a Saesol Disk AJ27, 6 lbf, in-situ 100%; Platen / Head Speed=97 / 91.

[0119] Zone Pressure: RR / Z1 / Z2 / Z3 / Z4 / Z5:5.90 / 5.10 / 2.40 / 2.15 / 2.10 / 2.20.

[0120] The wafer used was a Patten wafer: Semitech 754, Cu Blanket wafer Pre Thickness 10-12 KA.

[0121] Standardized polishing was performed on Cu and SiO2 film blanket wafers. After polishing, the wafers were cleaned using different cleaning compositions with the same machine program. After the cleaning process, the wafer defect increase value was scanned by the SURFSCAN SP7 machine of KLA-Tecor Company to verify the cleaning ability of the cleaning composition on the wafer.

[0122] <Corrosion rate of copper>

[0123] The film thickness of copper was measured by a four-probe resistivity meter, and the copper corrosion rate of the solution was calculated by the ratio of the thickness reduction amount and the processing time.

[0124] <Particle removal rate>

[0125] The patent disclosed method was selected to test the removal ability of different cleaning compositions on the residues and contaminants of Cu film wafers, see Chinese invention application CN110398500A.

[0126] <Organic residue removal force>

[0127] The organic residues removed by the cleaning solution are mainly insoluble metal organic complexes, and Cu-BTA complexes are the most common. Therefore, Cu-BTA complexes are used as standard substances to investigate the removal ability of the cleaning composition. By mixing equivalent amounts of CuSO4 and BTA in an aqueous solution (5wt%), a dark green suspension is obtained. The cleaning composition is diluted to 1 / 6 concentration with electronic grade deionized water, and the suspension is continuously added quantitatively until the solution becomes turbid, which is recorded as the termination point of the experiment. After each quantitative addition of the suspension, the solution is placed in a spectrophotometer for absorbance detection. According to the Lambert-Beer law,

[0128] A = lg(1 / T) = kbc,

[0129] The absorbance A and the transmittance T are logarithmically related, and the concentration c of the absorbing substance is proportional (k is the molar absorption coefficient, and b is the absorption layer thickness). Thus, the Cu-BTA complex dissolved in the solution is 2+ which is identified as the product after the dissolution of Cu-BTA, and can be characterized as the ability of the cleaning composition to remove Cu-BTA complexes. The total volume of the dissolved Cu-BTA suspension is recorded, which can be compared to the ability of the cleaning composition to remove organic residues after chemical mechanical polishing. The wavelength of 612 nm is selected for the spectrophotometric study, and the difference in absorbance can indicate the cleaning ability of the cleaning composition after chemical mechanical polishing.

[0130] <Measurement of surface tension and contact angle>

[0131] The surface tension was measured using the pendant drop method, and the contact angle was measured using the sessile drop method. A 2*2 cm copper sheet was immersed in 3% citric acid for 10 minutes, rinsed with deionized water, and dried, and then the contact angle of the 6-fold dilution was measured.

[0132] The physical parameters and performance evaluation of the post-CMP cleaning solution involved in the examples and comparative examples are shown in Table 2.

[0133] Table 2

[0134]

[0135] Compared with Comparative Examples 1-2, Examples 1-9 have stronger Cu-BTA removal ability and higher cleaning efficiency. Thus, it is shown that the electronic-grade quaternary ammonium base solution prepared by Synthetic Examples 1-8 and Synthetic Example 11 is suitable for use as a post-CMP cleaning solution for IC copper processes.

[0136] Although the present application has been described in detail with general description, specific embodiments and experiments, some modifications or improvements can be made on the basis of the present application, which is obvious to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present application, all belong to the scope of the present application claimed.

Claims

1. A quaternary ammonium alkaline solution containing tri-(2-hydroxyethyl)methylammonium hydroxide, characterized in that, The product is obtained by using a fluid reaction, through a tubular reactor or a microchannel reactor, with N-methyldiethanolamine and water as raw materials, reacting with ethylene oxide at a temperature of -50℃ to 50℃ for 1-60 minutes.

2. The quaternary ammonium alkaline solution according to claim 1, characterized in that, The tubular reactor or microchannel reactor may be a reactor made of non-metallic material or a metal reactor coated with non-metallic material; and / or, the total metal content of the raw material N-methyldiethanolamine and ethylene oxide is <50 ppb, and the raw material water is electronic grade pure water (single metal <1 ppb); and / or, the total metal content of the quaternary ammonium alkali solution is <35 ppb.

3. A method for preparing a quaternary ammonium alkaline solution containing tri-(2-hydroxyethyl)methylammonium hydroxide, characterized in that, A fluid reaction is employed, using a tubular reactor or a microchannel reactor, with N-methyldiethanolamine and water as raw materials, reacting with ethylene oxide at a temperature of -50℃ to 50℃ for 1-60 minutes to obtain a quaternary ammonium alkaline solution containing tris(2-hydroxyethyl)methylammonium hydroxide.

4. The method for preparing the quaternary ammonium alkali solution according to claim 3, characterized in that, The tubular reactor or microchannel reactor is a reactor made of non-metallic material or a metal reactor coated with non-metallic material; and / or, the total metal content of the raw materials N-methyldiethanolamine and ethylene oxide is <50 ppb, and the raw water is electronic grade pure water (single metal <1 ppb).

5. The method for preparing the quaternary ammonium alkali solution according to claim 3 or 4, characterized in that, Specifically, the steps include the following: Step 1: Mix N-methyldiethanolamine and water evenly in a clean container. Connect one end to the nitrogen pipeline to replace the atmosphere in the pipeline before and after feeding. Connect the other end to the feed inlet of the tubular reactor or microchannel reactor. Seal the other end for depressurization when the pipeline is blocked. Step II: The ethylene oxide inlet is connected to a tee via a plastic pipe. The other two ends of the tee are connected to nitrogen pipes and the inlet of the tubular reactor or microchannel reactor, respectively. The nitrogen pipes are used to purge the atmosphere in the pipes before and after feeding. Step III: Purge the entire apparatus from the storage bottle to the product collection bottle with nitrogen for 6-60 minutes to replace the atmosphere in the system with nitrogen; Step IV: Connect the tubular reactor or microchannel reactor and the integrated machine to the power supply, and control the pipeline temperature to -50℃ to 50℃; after the temperature stabilizes, introduce N-methyldiethanolamine aqueous solution and ethylene oxide gas at a fixed flow rate. After the raw materials are mixed, react in the reactor pipeline for 1-60 minutes. Step V: After all the product has flowed out of the outlet of the tubular reactor or microchannel reactor, flush the pipeline with nitrogen and bubble the product for 6-60 minutes. Finally, collect the quaternary ammonium base solution containing N-methyldiethanolamine and tris(2-hydroxyethyl)methylammonium hydroxide (THEMAH).

6. The method for preparing the quaternary ammonium alkali solution according to claim 3 or 4, characterized in that, The preferred reaction temperature for the N-methyldiethanolamine aqueous solution and ethylene oxide gas is -30℃ to 40℃.

7. The method for preparing the quaternary ammonium alkali solution according to claim 3 or 4, characterized in that, The molar ratio of N-methyldiethanolamine to ethylene oxide is 1:0.8-1.2, and the mass ratio of N-methyldiethanolamine to water is 1:0.1-3; and / or, the feed flow rate of the N-methyldiethanolamine aqueous solution is 0.077-0.926 kg / min, and the feed flow rate of ethylene oxide is 0.019-0.228 kg / min.

8. The application of a quaternary ammonium alkali solution as described in claim 1 or 2, or a quaternary ammonium alkali solution obtained by the preparation method according to any one of claims 3-7, characterized in that, The quaternary ammonium alkaline solution containing tri-(2-hydroxyethyl)methylammonium hydroxide is used as a cleaning agent, chemical polishing agent, solvent, complexing agent, developer, surfactant, electrolyte, analytical reagent, etc., and is preferably used for cleaning, etching or stripping of semiconductor formulations.

9. The application of a quaternary ammonium alkali solution in a cleaning composition after chemical mechanical polishing, characterized in that, The cleaning composition comprises the following components: pH adjuster 0.1 wt% to 10 wt%, quaternary ammonium alkali solution 1 wt% to 10 wt%, wetting agent 0.005 wt% to 1 wt%, and organophosphorus chelating agent 0.01 wt% to 5 wt%; wherein the quaternary ammonium alkali solution is the quaternary ammonium alkali solution according to claim 1 or 2 above or the quaternary ammonium alkali solution obtained by the preparation method according to any one of claims 3-7 above.

10. The application of the quaternary ammonium alkali solution as described in claim 9 in a post-chemical mechanical polishing cleaning composition, characterized in that, The pH is between 9 and 13; The amount of the quaternary ammonium alkali solution used is preferably 2% to 6% of the total weight of the cleaning composition; And / or, the amount of the wetting agent is preferably 0.01% to 1% of the total weight of the cleaning composition; And / or, the amount of the organophosphorus chelating agent is preferably 0.1% to 2% of the weight of the cleaning composition.

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