Leveling agent and preparation method thereof, copper electroplating solution and copper electroplating method

Abstract

The invention relates to the technical field of electroplating, in particular to a leveling agent, a preparation method of the leveling agent, copper electroplating liquid and a copper electroplating method. The leveling agent includes a functional component that is a reaction product comprising one or more cyclic secondary amine compounds or salts thereof, one or more dihaloalkyl ethers, one or more diepoxy compounds. When the leveling agent provided by the invention is used for copper electroplating liquid and copper electroplating treatment, electroplating processing of different space geometric structures on the surface of a substrate can be met, the leveling agent has good deep plating capacity and blind hole filling effect, and a formed copper plating layer is uniform in grain size, few in crystal defect and excellent in uniform corrosion capacity; the problem that hole-shaped corrosion pits appear after acid etching is effectively avoided, and the reliability of the copper interconnection layer prepared through the lamination method is guaranteed.

Description

Technical Field

[0001] The present application relates to the field of electroplating technology, and in particular to a leveling agent and a preparation method thereof, a copper electroplating solution and a copper electroplating method. Background Art

[0002] As electronic products develop towards precision, intelligence, lightness, and multifunctional integration, the size of printed circuit boards (PCBs) continues to shrink, and the line distribution density continues to increase, resulting in the emergence of high-density interconnection (HDI) circuit boards. HDI circuit boards are usually made by the general build-up method, also known as build-up multilayer PCBs (BUM-PCBs).

[0003] In the mature manufacturing method of multilayer boards using the build-up method, after the copper plating process is used to form the copper coating, it is often necessary to use an acidic etching solution to etch and thin it to obtain a specified coating thickness. However, the copper coating is prone to form hole-shaped corrosion pits after acid etching, which seriously affects the conductivity of the copper coating and the bonding performance between the copper coating and the substrate. Summary of the invention

[0004] Based on this, it is necessary to provide a leveling agent and a preparation method thereof, a copper electroplating solution and a copper electroplating method to solve the problem that the copper plating layer is prone to pitting after acid etching.

[0005] The above-mentioned purpose of the present application is achieved through the following technical solutions:

[0006] In a first aspect of the present application, a leveler is provided, comprising an effective component, wherein the effective component is a reaction product comprising one or more cyclic secondary amine compounds or salts thereof, one or more dihalogenated alkyl ethers, and one or more diepoxide compounds.

[0007] In some embodiments, the cyclic secondary amine compound has any one of the structures shown in general formula (I-1), (I-2) and (I-3):

[0008] (I-1); (I-2); (I-3);

[0009] Wherein, each occurrence of R1, R2 and R3 is independently selected from H or C1~C6 alkyl.

[0010] In some embodiments, the dihaloalkyl ether has a structure as shown in formula (II):

[0011] (II);

[0012] Wherein, n is selected from any integer between 1 and 50, and X is a halogen;

[0013] Each occurrence of R4 is independently selected from H or C1~C4 alkyl.

[0014] In some embodiments, the diepoxide compound has a structure as shown in the general formula (III):

[0015] (III)

[0016] Wherein, R5 is selected from -(CH2) a -or-CH2O(CH2) b OCH2-;

[0017] a and b are each independently selected from any integer between 1 and 10;

[0018] Each occurrence of R6 is independently selected from H or C1~C4 alkyl.

[0019] In some embodiments, the cyclic secondary amine compound includes one or more of pyrrolidine, 2-methylpyrrolidine, 3-methylpyrrolidine, 2-ethylpyrrolidine, 3-ethylpyrrolidine, morpholine, 2-methylmorpholine, 3-methylmorpholine, 2-ethylmorpholine, 3-ethylmorpholine, piperidine, 2-methylpiperidine, 3-methylpiperidine, 4-methylpiperidine, 2-ethylpiperidine, 3-ethylpiperidine and 4-ethylpiperidine.

[0020] In some embodiments, the dihaloalkyl ether includes one or more of bis(2-chloroethyl) ether, 1,2-bis(2-chloroethoxy)ethane, and diethylene glycol bis(2-chloroethyl) ether.

[0021] In some embodiments, the diepoxide compound includes one or more of 1,4-butanediol diglycidyl ether, 1,2-ethylenediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,2-propylenediol diglycidyl ether, 1,10-decanediol diglycidyl ether, 1,2,5,6-diepoxyhexane, and 1,2,7,8-diepoxyoctane.

[0022] In some embodiments, the molar ratio of the cyclic secondary amine compound or its salt, the dihalogenated alkyl ether and the diepoxide compound is 1:(0.1-0.7):(0.1-1.5).

[0023] In some embodiments, the number average molecular weight of the effective ingredient is 500-20,000.

[0024] In a second aspect of the present application, a method for preparing the leveling agent as described above is provided, comprising the following steps:

[0025] A cyclic secondary amine compound or a salt thereof and a dihalogenated alkyl ether are subjected to a nucleophilic substitution reaction to obtain an intermediate;

[0026] The intermediate and the diepoxy compound are subjected to a ring-opening polymerization reaction to obtain the leveling agent.

[0027] In a third aspect of the present application, a copper electroplating solution is provided, comprising the leveling agent as described above, or comprising a leveling agent prepared by the method for preparing the leveling agent as described above;

[0028] The concentration of the leveler in the copper electroplating solution is 5ppm-1000ppm.

[0029] In a fourth aspect of the present application, a copper electroplating method is provided, comprising the following steps:

[0030] The copper electroplating solution as described above is used to electroplating the substrate to form a copper plating layer.

[0031] This application has at least the following beneficial effects:

[0032] The effective component of the leveling agent provided in the present application is a class of oligomers with cyclic secondary amine characteristic functional groups, which can be adsorbed on the surface of the coating during the electroplating process and form a molecular barrier layer. The molecular barrier layer can not only increase the electrochemical polarization of the copper ion deposition reaction, but also promote the nucleation process, increase the number of crystal nuclei and refine the grains when the electrocrystallization overpotential becomes larger; it can also effectively control the brightener molecules in the plating solution to be adsorbed on the surface of the coating in an orderly and uniform manner through its special molecular structure and steric hindrance, so that the brightener molecules at all places on the surface of the coating have the same surface adsorption concentration, thereby forming an adsorption layer with a similar interface molecular organization structure on the surface of the coating, which is conducive to ensuring the consistency of copper electrocrystallization growth.

[0033] By using an electroplating solution containing the leveling agent provided in the present application, a coating with a finer and more uniform grain size can be obtained. Moreover, due to similar copper electrocrystallization growth kinetics, crystal defects in the coating also have similar spatial distribution patterns, so that each part of the coating surface has the same corrosion rate when subjected to chemical corrosion, which can effectively reduce the selective corrosion phenomenon caused by concentrated areas of crystal defects in the coating.

[0034] The leveling agent provided in the present application is used in copper electroplating solution and copper electroplating treatment, which can not only meet the electroplating processing of different spatial geometric structures on the surface of the substrate, but also has good deep plating ability and blind hole filling effect. In addition, the grain size of the formed copper plating layer is uniform and the crystal defects are few. It has excellent uniform corrosion ability, effectively avoids the problem of hole-shaped corrosion pits after acid etching, and ensures the reliability of preparing the copper interconnect layer by the build-up method. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application and to more completely understand the present application and its beneficial effects, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0036] Figure 1 This is a slice diagram after blind hole filling in Example 1;

[0037] Figure 2 for Figure 1 The top corrosion effect of the blind hole after acid etching is shown;

[0038] Figure 3 This is a slice diagram after blind hole filling in Example 2;

[0039] Figure 4 for Figure 3 The top corrosion effect of the blind hole after acid etching is shown;

[0040] Figure 5 This is a top corrosion effect diagram after blind hole filling and acid etching of Comparative Example 1;

[0041] Figure 6 This is a diagram showing the top corrosion effect after blind hole filling and acid etching in Comparative Example 2. DETAILED DESCRIPTION

[0042] In order to facilitate the understanding of the present application, the present application is further described in detail below in conjunction with specific embodiments. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0044] In the present application, the meaning of "and / or" includes any and all combinations of one or more related listed items. "At least one" means more than one, such as one, two and more than two. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layer" means at least two layers, such as two layers, three layers, etc., unless otherwise clearly and specifically defined. In the description of the present application, "several" means at least one, such as one, two, etc., unless otherwise clearly and specifically defined.

[0045] When a numerical range is disclosed in this application, the above range is considered to be continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed in this application should be understood to include any and all subranges included therein.

[0046] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0047] In this application, "above" or "below" includes the number itself. For example, "1 below" includes 1.

[0048] The temperature parameters in this application, unless otherwise specified, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0049] In the present application, room temperature refers to indoor temperature, normal temperature or general temperature. Generally speaking, the range of room temperature can be any one of the following temperature intervals: 23°C ± 2°C, 25°C ± 5°C or 20°C ± 5°C.

[0050] the term

[0051] Unless otherwise specified or there is a contradiction, the terms and phrases used in this application have the following meanings:

[0052] In the present application, when a substituent with the same symbol appears multiple times, each substituent may be the same or different from each other. For example, when a general formula contains multiple R, R may be the same or different from each other.

[0053] "Alkyl" refers to a monovalent residue formed by the loss of a hydrogen atom from a saturated hydrocarbon containing a primary (normal) carbon atom, a secondary carbon atom, a tertiary carbon atom, a quaternary carbon atom, or a combination thereof. Alkyl can represent a straight chain, branched and / or cyclic alkyl group. The carbon number of the alkyl group can be 1 to 50, 1 to 30, 1 to 20, 1 to 10 or 1 to 6. Phrases containing this term, for example, "C1 to C9 alkyl" refers to an alkyl group containing 1 to 9 carbon atoms, and each occurrence can be independently C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, C7 alkyl, C8 alkyl or C9 alkyl. Suitable examples include, but are not limited to, methyl (Me, -CH3), ethyl (Et, -CH2CH3), 1-propyl (n-Pr, n-propyl, -CH2CH2CH3), 2-propyl (i-Pr, i-propyl, -CH(CH3)2), 1-butyl (n-Bu, n-butyl, -CH2CH2CH2CH3), 2-methyl-1-propyl (i-Bu, i-butyl, -CH2CH(CH3)2), 2-butyl (s-Bu, s-butyl, -CH(C H3)CH2CH3), 2-methyl-2-propyl (t-Bu, t-butyl, -C(CH3)3), 1-pentyl (n-pentyl, -CH2CH2CH2CH2CH3), 2-pentyl (-CH(CH3)CH2CH2CH3), 3-pentyl (-CH(CH2CH3)2), 2-methyl-2-butyl (-C(CH3)2CH2CH3), 3-methyl-2-butyl (-CH(CH3)CH(CH3)2), 3-methyl-1-butyl (- CH2CH2CH(CH3)2), 2-methyl-1-butyl (-CH2CH(CH3)CH2CH3), 1-hexyl (-CH2CH2CH2CH2CH2CH3), 2-hexyl (-CH(CH3)CH2CH2CH2CH3), 3-hexyl (-CH(CH2CH3)(CH2CH2CH3)), 2-methyl-2-pentyl (-C(CH3)2CH2CH2CH3), 3-methyl-2-pentyl (-CH(CH3)CH( CH3)CH2CH3), 4-methyl-2-pentyl (-CH(CH3)CH2CH(CH3)2), 3-methyl-3-pentyl (-C(CH3)(CH2CH3)2), 2-methyl-3-pentyl (-CH(CH2CH3)CH(CH3)2), 2,3-dimethyl-2-butyl (-C(CH3)2CH(CH3)2), 3,3-dimethyl-2-butyl (-CH(CH3)C(CH3)3, octyl (-(CH2)7CH3).

[0054] "Alkylene" refers to a hydrocarbon group with two monovalent radical centers derived from an alkyl group by removing a hydrogen atom, which can be a saturated branched alkyl group or a saturated straight chain alkyl group. 10 "Alkylene" means that the alkyl portion contains 1 to 10 carbon atoms, and each occurrence can be independently C1 alkylene, C4 alkylene, C5 alkylene, C6 alkylene, C7 alkylene, C8 alkylene, C9 alkylene or C 10 Alkylene. Suitable examples include, but are not limited to, methylene (—CH2—), 1,1-ethyl (—CH(CH3)—), 1,2-ethyl (—CH2CH2—), 1,1-propyl (—CH(CH2CH3)—), 1,2-propyl (—CH2CH(CH3)—), 1,3-propyl (—CH2CH2CH2—), and 1,4-butyl (—CH2CH2CH2CH2—).

[0055] "Halogen" refers to F, Cl, Br or I.

[0056] In the copper electroplating method, it is necessary to use a copper electroplating solution to uniformly deposit copper on a substrate with irregular surface morphology, and effectively control the deposition rate to obtain good deep plating ability and blind hole filling effect. A study proposed a leveler for copper electroplating solution, which is a reaction product of a guanidine compound or its salt, a polyepoxide and a polyhalide, and evaluated the dispersion ability of the copper electroplating solution and the crystal thermal reliability of the copper plating layer. A study proposed an imidazole urea polymer for filling recessed structures and constructing columnar protrusion structures in a copper plating bath, and tested the performance of copper electroplating solution in filling blind holes.

[0057] However, these studies have only focused on the performance of copper electroplating solutions for electroplating different spatial geometric structures on the surface of the substrate, but lack testing and evaluation of the crystal corrosion performance of the copper coating. When electroplating is performed using traditional copper electroplating solutions, the copper coating obtained is prone to form pits after acid etching, and the severity of the pits is proportional to the concentration of the acid etching solution and the etching time. The hole diameter of this pit is within 10μm and the depth is 5μm~6μm. It is not only irregularly distributed on the surface of the substrate, but also densely distributed on the top of the blind hole after filling.

[0058] The applicant has found through research that the leveling agent in the copper electroplating solution has a significant impact on the quality of the copper coating. During the electroplating process, the traditional leveling agent will form an adsorption layer at the cathode interface and affect the electroplating crystallization process of copper, which is not conducive to obtaining a copper coating with uniform grain size and few crystal defects. Due to the obvious differences in the microscopic morphology and crystal structure of the copper coating, it produces different corrosion rates during the oxidation corrosion process, and forms obvious hole-shaped corrosion pits at locations with many crystal defects, especially at the top of the blind hole after filling.

[0059] Based on this, in the first aspect of the present application, a leveling agent is provided to solve the problem that the copper plating layer is prone to pitting after acid etching.

[0060] In some embodiments, the leveler includes a functional component, which is a reaction product comprising one or more cyclic secondary amine compounds or salts thereof, one or more dihalogenated alkyl ethers, and one or more diepoxide compounds.

[0061] In the present application, the effective ingredient refers to the component that mainly exerts its efficacy, which can be a pure compound or a composition obtained by mixing multiple compounds. That is, after the reaction, the reaction liquid can be separated and purified to obtain a pure compound, or it can be used directly without separation and purification.

[0062] The effective component of the leveling agent provided in the present application is a class of oligomers with cyclic secondary amine characteristic functional groups, which can be adsorbed on the surface of the coating during the electroplating process and form a molecular barrier layer. The molecular barrier layer can not only increase the electrochemical polarization of the copper ion deposition reaction, but also promote the nucleation process, increase the number of crystal nuclei and refine the grains when the electrocrystallization overpotential becomes larger; it can also effectively control the brightener molecules in the plating solution to be adsorbed on the surface of the coating in an orderly and uniform manner through its special molecular structure and steric hindrance, so that the brightener molecules at all places on the surface of the coating have the same surface adsorption concentration, thereby forming an adsorption layer with a similar interface molecular organization structure on the surface of the coating, which is conducive to ensuring the consistency of copper electrocrystallization growth.

[0063] By using an electroplating solution containing the leveling agent provided in the present application, a coating with a finer and more uniform grain size can be obtained. Moreover, due to similar copper electrocrystallization growth kinetics, crystal defects in the coating also have similar spatial distribution patterns, so that each part of the coating surface has the same corrosion rate when subjected to chemical corrosion, which can effectively reduce the selective corrosion phenomenon caused by concentrated areas of crystal defects in the coating.

[0064] The leveling agent provided in the present application is used in copper electroplating solution and copper electroplating treatment, which can not only meet the electroplating processing of different spatial geometric structures on the surface of the substrate, but also has good deep plating ability and blind hole filling effect. In addition, the grain size of the formed copper plating layer is uniform and the crystal defects are few. It has excellent uniform corrosion ability, effectively avoids the problem of hole-shaped corrosion pits after acid etching, and ensures the reliability of preparing the copper interconnect layer by the build-up method.

[0065] In some embodiments, the cyclic secondary amine compound has any one of the structures shown in formula (I-1), (I-2) and (I-3):

[0066] (I-1); (I-2); (I-3);

[0067] Wherein, each occurrence of R1, R2 and R3 is independently selected from H or C1~C6 alkyl.

[0068] It can be understood that in the cyclic secondary amine compound, R1, R2 and R3 can replace any position on the heterocyclic ring except the N atom and the O atom, and the number of R1, R2 and R3 can be one or more, and the number of R1, R2 and R3 on the same substitution site can also be one or more. Specifically, R1 can be located at the ortho or meta position of the N atom, R2 can be located at the ortho, meta or para position of the N atom, and R3 can be located at the ortho or meta position of the N atom (or O atom).

[0069] As an example, each occurrence of R1, R2 and R3 is independently selected from any one of H, C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl and C6 alkyl, and suitable examples include but are not limited to: H, -CH3, -CH2CH3, -CH2CH2CH3, -CH(CH3)2, -CH2CH2CH2CH3, -CH2CH(CH3)2, -CH(CH3)CH2CH3, -C(CH3)3, -CH2CH2CH2CH2CH3, -CH(CH3)CH2CH3, -CH(CH3)CH2CH3, -CH(CH2CH3)2, -C(CH3)2CH2CH3, -CH(CH3)CH R1, R2 and R3 are each independently selected from any one of H, -CH3, -CH2CH3, -CH2CH2CH2CH2CH3 and -CH(CH3)2.

[0070] In some embodiments, as shown in Table 1, the cyclic secondary amine compound includes one or more of pyrrolidine, 2-methylpyrrolidine, 3-methylpyrrolidine, 2-ethylpyrrolidine, 3-ethylpyrrolidine, morpholine, 2-methylmorpholine, 3-methylmorpholine, 2-ethylmorpholine, 3-ethylmorpholine, piperidine, 2-methylpiperidine, 3-methylpiperidine, 4-methylpiperidine, 2-ethylpiperidine, 3-ethylpiperidine and 4-ethylpiperidine.

[0071] Table 1. Cyclic secondary amine compounds

[0072]

[0073]

[0074] In some embodiments, the salt of the cyclic secondary amine compound includes at least one of hydrochloride, hydrobromide and hydroiodide. For example, the salt of the cyclic secondary amine compound includes but is not limited to: 2-methylmorpholine hydrochloride, 2-ethylmorpholine hydrochloride, 2-methylpyrrolidine hydrochloride or 3-methylpyrrolidine hydrochloride.

[0075] In some embodiments, the dihaloalkyl ether has a structure as shown in the general formula (II):

[0076] (II);

[0077] Wherein, n is selected from any integer between 1 and 50, and X is a halogen;

[0078] Each occurrence of R4 is independently selected from H or C1~C4 alkyl.

[0079] It is understood that in dihaloalkyl ether, n represents the degree of polymerization. As an example, the value of n includes but is not limited to 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20, and can further be 1 to 5.

[0080] As an example, X represents a halogen, and each occurrence of X is independently selected from any one of F, Cl, Br and I, and may further be Cl or Br.

[0081] As an example, each occurrence of R4 is independently selected from any one of H, C1 alkyl, C2 alkyl, C3 alkyl and C4 alkyl, and suitable examples include, but are not limited to, H, -CH3, -CH2CH3, -CH2CH2CH3, -CH(CH3)2, -CH2CH2CH2CH3, -CH2CH(CH3)2, -CH(CH3)CH2CH3 and -C(CH3)3. Further optionally, each occurrence of R4 is independently selected from H or -CH3.

[0082] In some embodiments, as shown in Table 2, the dihaloalkyl ether includes one or more of bis(2-chloroethyl)ether, 1,2-bis(2-chloroethoxy)ethane, and diethylene glycol bis(2-chloroethyl)ether.

[0083] Table 2. Dihaloalkyl ethers

[0084]

[0085] In some embodiments, the diepoxide has a structure as shown in Formula (III):

[0086] (III)

[0087] Wherein, R5 is selected from Y or -CH2O-Y-OCH2-, and Y is selected from C1~C 10 Alkylene;

[0088] Each occurrence of R6 is independently selected from H or C1~C4 alkyl.

[0089] It can be understood that in the diepoxy compound, when R5 is selected from Y, R5 is an alkylene group; when R5 is selected from -CH2O-Y-OCH2-, R5 is an alkyleneoxy group containing two ether bonds (-O-).

[0090] As an example, Y is selected from C1 alkylene, C4 alkylene, C5 alkylene, C6 alkylene, C7 alkylene, C8 alkylene, C9 alkylene or C 10 Any of alkylene. Meanwhile, Y can be selected from branched alkylene or branched alkylene. Suitable examples include, but are not limited to: -CH2-, -CH(CH3)-, -CH2CH2-, -CH(CH2CH3)-, -CH2CH(CH3)-, -CH2CH2CH2- and -CH2CH2CH2CH2-.

[0091] Further, Y is selected from -(CH2) a -, a is selected from any integer in the range of 1 to 10. a represents the number of repeating units of methylene, and the value of a independently includes but is not limited to 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, and can further be selected from 1 to 6.

[0092] As an example, each occurrence of R6 is independently selected from any one of H, C1 alkyl, C2 alkyl, C3 alkyl and C4 alkyl, and suitable examples include but are not limited to: H, -CH3, -CH2CH3, -CH2CH2CH3, -CH(CH3)2, -CH2CH2CH2CH3, -CH2CH(CH3)2, -CH(CH3)CH2CH3 and -C(CH3)3. Further optionally, each occurrence of R6 is independently selected from H or -CH3.

[0093] In some embodiments, as shown in Table 3, the diepoxide compound includes one or more of 1,4-butanediol diglycidyl ether, 1,2-ethylenediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,2-propylenediol diglycidyl ether, 1,10-decanediol diglycidyl ether, 1,2,5,6-diepoxyhexane, and 1,2,7,8-diepoxyoctane.

[0094] Table 3. Diepoxides

[0095]

[0096] In some embodiments, the molar ratio of the cyclic secondary amine compound or its salt, the dihalogenated alkyl ether and the diepoxy compound is 1:(0.1-0.7):(0.1-1.5). As an example, the molar ratio of the cyclic secondary amine compound or its salt and the dihalogenated alkyl ether includes, but is not limited to, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6 or 1:0.7, and may further be 1:(0.1-0.4); 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4 or 1:1.5, and may further be 1:(0.1-0.8).

[0097] It is understandable that the number average molecular weight of the functional component in the leveling agent can be appropriately adjusted as needed. In some embodiments, the number average molecular weight of the functional component is 500-20000. As an example, the number average molecular weight of the functional component includes but is not limited to 500, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 11000, 12000, 13000, 14000, 15000, 16000, 17000, 18000, 19000 or 20000. Further, the number average molecular weight of the functional component is 500-5000. Further, the number average molecular weight of the functional component is 500-2000.

[0098] In a second aspect of the present application, a method for preparing a leveling agent is provided, which is used to prepare the above-mentioned leveling agent.

[0099] In some embodiments, the method for preparing the leveler comprises the following steps:

[0100] S100: subjecting a cyclic secondary amine compound or a salt thereof to a nucleophilic substitution reaction with a dihalogenated alkyl ether to obtain an intermediate;

[0101] S200: subjecting the intermediate and the diepoxide compound to a ring-opening polymerization reaction to obtain the leveling agent.

[0102] In the preparation method of the leveler provided in the present application, the cyclic secondary amine compound has only one active nitrogen atom, the dihaloalkyl ether contains two halogen atoms, and a nucleophilic substitution reaction (or N-alkylation reaction) occurs between the active nitrogen atom on the cyclic secondary amine compound and the halogen atom of the dihaloalkyl ether, thereby obtaining an intermediate. The diepoxide compound can further undergo a ring-opening polymerization reaction with the active nitrogen atom on the intermediate, thereby obtaining a leveler having a cyclic secondary amine and an ether bond and having little steric hindrance.

[0103] In some embodiments, a cyclic secondary amine compound or a salt thereof and a dihalogenated alkyl ether are subjected to a nucleophilic substitution reaction, comprising the following steps:

[0104] S110: mixing a cyclic secondary amine compound or a salt thereof, a dihalogenated alkyl ether, an inorganic base and an organic solvent, reacting at 10° C. to 40° C. for 8 h to 24 h, and performing purification treatment to obtain an intermediate; or,

[0105] S120: mixing a cyclic secondary amine compound or a salt thereof, a dihalogenated alkyl ether and an organic solvent, reacting at 60° C. to 90° C. for 6 h to 12 h, and performing purification treatment to obtain an intermediate.

[0106] It can be understood that adding a suitable inorganic base is beneficial to lowering the reaction temperature of the nucleophilic substitution reaction.

[0107] In some embodiments, in step S110, in the presence of an inorganic base, the reaction temperature of the nucleophilic substitution reaction includes but is not limited to: 10°C, 12°C, 15°C, 18°C, 20°C, 22°C, 25°C, 28°C, 30°C, 32°C, 35°C, 38°C or 40°C, and may further be 20°C to 30°C; the reaction time of the nucleophilic substitution reaction includes but is not limited to: 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h or 24h, and may further be 10h to 16h. In some specific examples, in the presence of an inorganic base, the reaction conditions of the nucleophilic substitution reaction are: overnight reaction (~16h) at room temperature (~25°C).

[0108] In some embodiments, in step S120, in the absence of an inorganic base, the reaction temperature of the nucleophilic substitution reaction includes, but is not limited to, 60°C, 62°C, 65°C, 68°C, 70°C, 72°C, 75°C, 78°C, 80°C, 82°C, 85°C, 88°C or 90°C, and may further be 65°C to 75°C; the reaction time of the nucleophilic substitution reaction includes, but is not limited to, 6h, 7h, 8h, 9h, 10h, 11h or 12h, and may further be 7h to 9h. In some specific examples, in the absence of an inorganic base, the reaction conditions of the nucleophilic substitution reaction are: 8h at 70°C.

[0109] In some embodiments, the inorganic base includes one or more of sodium carbonate (Na2CO3), potassium carbonate (Na2CO3), sodium hydroxide (NaOH), and potassium hydroxide (KOH).

[0110] In some embodiments, the molar ratio of the cyclic secondary amine compound or its salt to the inorganic base is 1:(0.8-1). As an example, the molar ratio of the cyclic secondary amine compound or its salt to the inorganic base includes but is not limited to 1:0.8, 1:0.85, 1:0.9, 1:0.95 or 1:1.

[0111] In some embodiments, the organic solvent includes one or more of dichloromethane, chloroform, petroleum ether, tetrahydrofuran, acetone, and acetonitrile.

[0112] In some embodiments, the molar volume ratio of the cyclic secondary amine compound or its salt to the organic solvent is 0.5 mol / L to 1.5 mol / L, that is, 0.5 mol to 1.5 mol of the cyclic secondary amine compound or its salt is added to 1 L of organic solvent. As an example, the molar volume ratio of the cyclic secondary amine compound or its salt to the organic solvent includes but is not limited to 0.5 mol / L, 0.6 mol / L, 0.8 mol / L, 1 mol / L, 1.2 mol / L, 1.4 mol / L or 1.5 mol / L.

[0113] In some embodiments, the purification process includes one or more of filtration, washing, drying, rotary evaporation, centrifugation and chromatography, and the filtration includes one or more of ordinary filtration, vacuum filtration (or suction filtration) and filter press. In some specific examples, the purification process includes the following steps: vacuum filtration of the mixture obtained by the nucleophilic substitution reaction to remove the generated by-products (such as salt impurities of sodium chloride, potassium chloride or cyclic secondary amine compounds); washing with an organic solvent for 1 to 5 times, and removing the organic solvent and excess cyclic secondary amine compounds by rotation to obtain an intermediate.

[0114] In some embodiments, the intermediate and the diepoxide are subjected to a ring-opening polymerization reaction, comprising the steps of:

[0115] S210: Mix the intermediate, diepoxide and pure water, and react at 50°C~80°C for 0.5h~2h.

[0116] S220: adjust the pH value to 7.5-8.5, and react at 60-100°C for 5-8 hours;

[0117] S230: Cool to room temperature and adjust the pH value to 1.5-2.5 to obtain a leveling agent.

[0118] As an example, in step S210, the reaction temperature includes, but is not limited to, 50°C, 52°C, 55°C, 58°C, 60°C, 62°C, 65°C, 68°C, 70°C, 72°C, 75°C, 78°C, or 80°C; the reaction time includes, but is not limited to, 0.5h, 0.8h, 1h, 1.2h, 1.5h, 1.8h, or 2h. In some specific examples, the reaction condition of step S210 is: react at 60°C for 1h.

[0119] As an example, in step S220, the pH value of the reaction system includes but is not limited to: 7.5, 7.6, 7.7, 7.8, 7.9, 8, 8.1, 8.2, 8.3, 8.4 or 8.5; the reaction temperature includes but is not limited to: 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C; the reaction time includes but is not limited to 5h, 5.5h, 6h, 6.5h, 7h, 7.5h or 8h. In some specific examples, the reaction conditions of step S220 are: adjusting the pH value to 8 and reacting at 80°C for 6h.

[0120] As an example, in step S230, the pH value of the reaction system includes but is not limited to: 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4 or 2.5. In some specific examples, the reaction conditions of step S230 are: after cooling to room temperature, adjusting the pH value to 2.

[0121] In some embodiments, the molar volume ratio of the diepoxide to pure water is 0.5 mol / L to 1.5 mol / L, that is, 0.5 mol to 1.5 mol of the diepoxide is added to 1 L of pure water. As an example, the molar volume ratio of the diepoxide to pure water includes but is not limited to 0.5 mol / L, 0.6 mol / L, 0.8 mol / L, 1 mol / L, 1.2 mol / L, 1.4 mol / L or 1.5 mol / L.

[0122] In some embodiments, the method for adjusting the pH value comprises the following steps: adjusting the pH value of the reaction system using an acid solution. The acid in the acid solution comprises one or more of H2SO4, HNO3 and HCl, and the mass fraction of the acid in the acid solution is 30% to 60%, for example, 30%, 35%, 40%, 45%, 50%, 55% or 60%. In some specific examples, the pH value of the reaction system is adjusted using a H2SO4 solution with a mass fraction of 50%.

[0123] In a third aspect of the present application, a copper electroplating solution is provided, comprising the leveling agent described in the first aspect of the present application, or a leveling agent prepared by the preparation method of the leveling agent described in the second aspect of the present application.

[0124] In some embodiments, the concentration of the leveler in the copper electroplating solution is 5 ppm to 1000 ppm.

[0125] As an example, the concentration of the leveler in the copper electroplating solution includes but is not limited to: 5ppm, 10ppm, 20ppm, 30ppm, 40ppm, 50ppm, 60ppm, 70ppm, 80ppm, 90ppm, 100ppm, 200ppm, 300ppm, 400ppm, 500ppm, 600ppm, 700ppm, 800ppm, 900ppm or 1000ppm, and can further be selected from 10ppm to 800ppm, and further can be selected from 20ppm to 40ppm.

[0126] In some embodiments, the copper electroplating solution further includes a metal ion source, a hydrogen ion source, a chloride ion source, a brightener and an inhibitor. The brightener, also known as an accelerator, is mainly used to compete with the leveler for adsorption on the cathode surface and participate in the electrochemical reaction to change the microstructure of the copper coating, thereby making the coating surface brighter; the inhibitor is used to inhibit the electroplating rate of the metal;

[0127] In some embodiments, the metal ion source comprises a copper salt. By way of example, copper salts include, but are not limited to, copper sulfate, ferric nitrate, copper acetate, copper chloride, copper perchlorate, copper tetrafluoroborate, copper gluconate, copper sulfamate, copper alkyl sulfonates (such as copper methane sulfonate, copper ethane sulfonate or copper propane sulfonate), and copper aryl sulfonates (such as copper benzene sulfonate or copper p-toluene sulfonate).

[0128] In some embodiments, the copper salt providing the metal ion source may be copper sulfate pentahydrate, and the concentration of copper sulfate pentahydrate in the copper electroplating solution is 180 g / L to 250 g / L. As an example, the concentration of copper sulfate pentahydrate in the copper electroplating solution may be 180 g / L, 190 g / L, 200 g / L, 210 g / L, 220 g / L, 230 g / L, 240 g / L, or 250 g / L.

[0129] In some embodiments, the hydrogen ion source includes sulfuric acid, nitric acid, hydrochloric acid, hydrobromic acid, perchloric acid, acetic acid, phosphoric acid, sulfamic acid, alkyl sulfonic acid (such as methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid or trifluoromethanesulfonic acid), aryl sulfonic acid (such as benzenesulfonic acid or p-toluenesulfonic acid).

[0130] In some embodiments, the inorganic acid providing the hydrogen ion source may be sulfuric acid, and the concentration of sulfuric acid in the copper electroplating solution is 30 g / L to 80 g / L. As an example, the concentration of sulfuric acid in the copper electroplating solution may be 30 g / L, 40 g / L, 50 g / L, 60 g / L, 70 g / L, or 80 g / L.

[0131] In some embodiments, the chloride ion source includes but is not limited to sodium chloride, potassium chloride, etc. The concentration of the chloride ion source in the copper electroplating solution is 30ppm to 80ppm. As an example, the concentration of the chloride ion source in the copper electroplating solution can be 30ppm, 40ppm, 50ppm, 60ppm, 70ppm or 80ppm.

[0132] Understandably, in copper plating solution, 1ppm=1mg / L.

[0133] In some embodiments, the brightener includes one or more of sodium N,N-dimethyldithioamate, sodium polydisulfide propane sulfonate, sodium 3-mercaptopropane sulfonate, and sodium 3-(benzothiazole-2-mercapto)propane sulfonate.

[0134] In some embodiments, the concentration of the brightener in the copper electroplating solution is 0.05ppm to 20ppm. As an example, the concentration of the brightener in the copper electroplating solution can be 0.05ppm, 0.1ppm, 0.5ppm, 1ppm, 2ppm, 4ppm, 6ppm, 8ppm, 10ppm, 12ppm, 14ppm, 16ppm, 18ppm or 20ppm.

[0135] In some embodiments, the inhibitor includes polypropylene glycol copolymers and polyethylene glycol copolymers, such as ethylene oxide-propylene oxide copolymers, butanol-ethylene oxide-propylene oxide copolymers.

[0136] In some embodiments, the concentration of the inhibitor in the copper electroplating solution is 100 ppm to 2000 ppm. As an example, the concentration of the inhibitor in the copper electroplating solution can be 100 ppm, 200 ppm, 400 ppm, 600 ppm, 800 ppm, 1000 ppm, 1200 ppm, 1400 ppm, 1600 ppm, 1800 ppm or 2000 ppm.

[0137] In some embodiments, the copper electroplating solution includes the following components in the following concentrations:

[0138] .

[0139] In a fourth aspect of the present application, a copper electroplating method is provided, comprising the following steps: using the copper electroplating solution described in the third aspect of the present application to electroplate a substrate to form a copper plating layer.

[0140] In some embodiments, the substrate surface is provided with at least one blind hole or at least one through hole;

[0141] The aperture of the blind hole is 40μm~200μm, and the depth of the blind hole is 20μm~150μm;

[0142] The aperture of the through hole is 100 μm~2 mm, and the depth of the through hole is 40 μm~10 mm.

[0143] It can be understood that the copper electroplating solution and copper electroplating method provided by the present application can meet the electroplating requirements of different spatial geometric structure characteristics on the substrate surface, such as forming a copper plating layer of a specified thickness, filling blind holes, grooves and through holes, thickening circuit lines, and depositing copper pillars. At the same time, the copper plating layer formed by electroplating has excellent uniform corrosion performance, which can effectively suppress the problem of hole-shaped corrosion pits that appear after acid etching, and ensure the reliability of the copper interconnect layer in the multilayer board made by the build-up method.

[0144] In some embodiments, the electroplating process conditions include: a current density of 10ASF to 50ASF, or a current density of 1ASD to 6ASD.

[0145] It can be understood that the electroplating effect of blind vias can be evaluated by the “surface copper thickness” and “hole filling ability” after the blind vias are filled.

[0146] Among them, "surface copper thickness" refers to the thickness of the copper plating deposited on the surface of the substrate after the blind hole is filled. Generally speaking, the "surface copper thickness" varies according to the aperture size of the blind hole. The larger the aperture, the greater the "surface copper thickness" after the hole is filled. However, in order to meet the current process requirements of HDI circuit boards and fine circuit production, the "surface copper thickness" must still be ensured to be less than 35μm.

[0147] The "hole filling ability" is evaluated by measuring the dimple value, that is, the depression value of the copper plating thickness deposited in the blind hole relative to the surface of the copper plating deposited on the substrate surface. The closer the depression value is to 0 in the positive range, the better the hole filling ability of the copper electroplating solution. If the copper plating deposited in the blind hole protrudes from the surface of the copper plating on the substrate surface, the depression value is expressed as a negative number.

[0148] In some embodiments, after the blind hole is filled with copper electroplating solution, the surface copper thickness is ≤20 μm, and can be further ≤15 μm; the recess value of the blind hole is ≤10 μm, and can be further ≤5 μm.

[0149] The following is further described in conjunction with specific embodiments and comparative examples. The raw materials involved in the following specific embodiments and comparative examples, unless otherwise specified, can all be commercially available, the instruments used, unless otherwise specified, can all be commercially available, and the processes involved, unless otherwise specified, are all routinely selected by those skilled in the art.

[0150] Example 1

[0151] The preparation method of the leveling agent provided in this embodiment is as follows:

[0152] (1) In a 100 mL single-necked flask, 40 mmol of piperidine, 15 mmol of 1,2-di(2-chloroethoxy)ethane, 40 mL of dichloromethane, and 36 mmol of sodium carbonate were added, and the mixture was stirred at room temperature (~25°C) for overnight reaction (~16 h) to obtain a mixture.

[0153] (2) The mixture was filtered under reduced pressure to remove white solid impurities. The filter cake was washed three times with dichloromethane. The filtrate was evaporated using a rotary evaporator at room temperature (~25°C) to remove dichloromethane, thereby obtaining a light yellow liquid, which was the intermediate.

[0154] (3) Add 30 mL of pure water and 30 mmol of 1,4-butanediol diglycidyl ether to the intermediate, and stir the reaction in an oil bath at 60°C for 1 h. Use 50% by mass H2SO4 solution to adjust the pH value of the reaction system to 8, and heat to 80°C and continue stirring the reaction for 6 h. Cool to room temperature, and use 50% by mass H2SO4 solution to adjust the pH value of the reaction system to 2 to obtain an amber solution, which is the leveling agent.

[0155] (4) The amber solution of step (3) was tested by hydrogen nuclear magnetic resonance (HNMR) (solvent: heavy water, radio frequency: 300 MHz). The peak values ​​of chemical shift δ (in ppm) on the obtained hydrogen spectrum were as follows: 4.20~4.00 (m, 24H), 3.80~3.70 (m, 6H), 3.60~3.35 (m, 34H), 2.70~2.50 (m, 12H), 1.85~1.75 (m, 16H), 1.65~1.45 (m, 20H), thereby confirming the structure.

[0156] Example 2

[0157] The preparation method of the leveling agent provided in this embodiment is as follows:

[0158] (1) In a 250 mL single-necked flask, 90 mmol of piperidine, 15 mmol of 1,2-di(2-chloroethoxy)ethane and 80 mL of petroleum ether (boiling range 60-90°C) were added, and the mixture was stirred and reacted in an oil bath at 70°C for 8 hours to obtain a mixture.

[0159] (2) The mixture was cooled to room temperature and filtered under reduced pressure to remove white solid impurities (mainly piperidine hydrochloride). The filter cake was washed three times with petroleum ether. The filtrate was evaporated using a rotary evaporator at 70°C to remove petroleum ether and excess piperidine to obtain a light yellow liquid, which was the intermediate.

[0160] (3) Add 20 mL of pure water and 12 mmol of 1,4-butanediol diglycidyl ether to the intermediate, heat it in an oil bath, and stir the reaction at 60°C for 1 h. Use 50% by mass H2SO4 solution to adjust the pH value of the reaction system to 8, and heat it to 80°C and continue stirring the reaction for 6 h. Cool it to room temperature, and use 50% by mass H2SO4 solution to adjust the pH value of the reaction system to 2 to obtain an amber solution, which is the leveling agent.

[0161] (4) The amber solution of step (3) was tested by hydrogen nuclear magnetic resonance (HNMR) (solvent: heavy water, radio frequency: 300 MHz). The peak values ​​of chemical shift δ (in ppm) on the obtained hydrogen spectrum were as follows: 4.20~4.00 (m, 9.6H), 3.80~3.70 (m, 6H), 3.60~3.35 (m, 26.4H), 2.70~2.50 (m, 4.8H), 1.85~1.75 (m, 12H), 1.65~1.45 (m, 10.8H), thereby confirming the structure.

[0162] Example 3

[0163] This embodiment is basically the same as embodiment 1, except that the cyclic secondary amine compound is morpholine.

[0164] Example 4

[0165] This embodiment is basically the same as embodiment 2, except that pyrrolidine is used as the cyclic secondary amine compound.

[0166] Example 5

[0167] This embodiment is basically the same as embodiment 1, except that the dihalogenated alkyl ether is bis(2-chloroethyl) ether.

[0168] Example 6

[0169] This embodiment is basically the same as embodiment 2, except that diethylene glycol bis(2-chloroethyl) ether is used as the dihalogenated alkyl ether.

[0170] Example 7

[0171] This embodiment is basically the same as the embodiment 1, except that the diepoxide compound is 1,6-hexanediol diglycidyl ether.

[0172] Example 8

[0173] This embodiment is basically the same as Embodiment 2, except that the diepoxy compound is 1,2,7,8-diepoxyoctane.

[0174] Comparative Example 1

[0175] The difference between this comparative example and Example 1 is that the reaction raw material does not contain dihalogenated alkyl ether.

[0176] The preparation method of the leveling agent provided in this comparative example is as follows:

[0177] Add 40mmol of piperidine, 30mmol of 1,4-butanediol diglycidyl ether and 30mL of pure water into a 100mL single-necked flask, and stir the reaction in an oil bath at 60°C for 1h; adjust the pH value of the reaction system to 8 with a 50% mass fraction H2SO4 solution, and heat to 80°C and continue stirring the reaction for 6h; cool to room temperature, and adjust the pH value of the reaction system to 2 with a 50% mass fraction H2SO4 solution to obtain an amber solution, which is the leveling agent.

[0178] Comparative Example 2

[0179] The difference between this comparative example and Example 2 is that the reaction raw materials do not contain diepoxide compounds.

[0180] The preparation method of the leveling agent provided in this comparative example is as follows:

[0181] In a 250mL single-necked flask, add 90mmol of piperidine, 15mmol of 1,2-di(2-chloroethoxy)ethane and 80mL of acetonitrile, and stir the mixture in an oil bath at 70°C for 8h. Cool the mixture to room temperature to precipitate white crystals. Add 80mL of pure water and stir until all the white crystals are dissolved to obtain a brown-yellow liquid, which is the leveling agent.

[0182] Comparative Example 3

[0183] The difference between this comparative example and Example 2 is that the dihalogenated alkyl ether is replaced by 1,6-dichlorohexane.

[0184] Comparative Example 4

[0185] The difference between this comparative example and Example 2 is that the cyclic secondary amine compound is replaced by cyclohexylamine (cyclic primary amine compound).

[0186] Comparative Example 5

[0187] The difference between this comparative example and Example 1 is that the cyclic secondary amine compound is replaced by diethylamine (acyclic secondary amine compound).

[0188] Test Case

[0189] The leveling agents of each embodiment and each comparative example were prepared into a copper electroplating solution according to the formula of Table 4;

[0190] The substrate uses a double-sided FR4 PCB test board with a size of 5cm×15cm, a thickness of 1mm, a blind hole diameter of 100μm, and a blind hole depth of 75μm;

[0191] The substrate was placed in a Haring cell filled with copper electroplating solution and electroplated for 60 minutes at a current density of 1.61ASD (15ASF) to obtain a copper-plated substrate. The copper-plated substrate was then cut into slices to test the filling effect of the blind holes.

[0192] The copper-plated substrate was immersed in an acidic etching solution for acid etching. During the etching process, the copper-plated substrate was swung back and forth to enhance the corrosion effect. The etching process lasted for 2 minutes, and the thickness of the copper layer obtained by etching was about 3μm~5μm. Among them, the main components of the acidic etching solution include hydrogen peroxide, sulfuric acid and a small amount of corrosion inhibitor. The copper-plated substrate after acid etching was placed in a metallographic microscope to observe the pitting of the coating surface. The results are shown in Table 5 and Figures 1 to 6 .

[0193] As shown in Table 5, the copper plating solution prepared by the leveling agents of Examples 1 to 8 is used for copper plating treatment. In the obtained copper-plated substrate, the surface copper thickness is controlled between 9.88 μm and 18.26 μm, and the depression value is controlled between -8.83 and 7.39, indicating that the copper plating solution of Examples 1 to 8 has good deep plating ability and blind hole filling effect. At the same time, after the copper-plated substrate is subjected to acid etching, basically no hole-shaped corrosion pits will appear, indicating that the copper plating layer obtained in the embodiment has a finer and more uniform grain size, and less crystal defects, and exhibits excellent uniform corrosion ability during acid corrosion.

[0194] Table 4. Copper electroplating solution formula

[0195]

[0196] Table 5. Blind hole plating effect formula

[0197]

[0198] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0199] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of protection of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the attached claims.

Claims

1. A leveling agent, characterized in that: The invention comprises an effective component, which is a reaction product comprising one or more cyclic secondary amine compounds or salts thereof, one or more dihalogenated alkyl ethers, and one or more diepoxy compounds.

2. The leveling agent according to claim 1, characterized in that The cyclic secondary amine compound has any one of the structures shown in general formula (I-1), (I-2) and (I-3): （Ⅰ-1）； （Ⅰ-2）； （Ⅰ-3）； Wherein, each occurrence of R1, R2 and R3 is independently selected from H or C1~C6 alkyl.

3. The leveling agent according to claim 1, characterized in that The dihalogenated alkyl ether has a structure as shown in the general formula (II): （Ⅱ）； Wherein, n is selected from any integer between 1 and 50, and X is a halogen; Each occurrence of R4 is independently selected from H or C1~C4 alkyl.

4. The leveling agent according to claim 1, characterized in that The diepoxy compound has a structure as shown in the general formula (III): （Ⅲ） Wherein, R5 is selected from -(CH2) a -or-CH2O(CH2) b OCH2-; a and b are each independently selected from any integer between 1 and 10; Each occurrence of R6 is independently selected from H or C1~C4 alkyl.

5. The leveling agent according to any one of claims 1 to 4, characterized in that One or more of the following conditions are met: (1) The cyclic secondary amine compound includes one or more of pyrrolidine, 2-methylpyrrolidine, 3-methylpyrrolidine, 2-ethylpyrrolidine, 3-ethylpyrrolidine, morpholine, 2-methylmorpholine, 3-methylmorpholine, 2-ethylmorpholine, 3-ethylmorpholine, piperidine, 2-methylpiperidine, 3-methylpiperidine, 4-methylpiperidine, 2-ethylpiperidine, 3-ethylpiperidine and 4-ethylpiperidine; (2) The dihaloalkyl ether includes one or more of bis(2-chloroethyl) ether, 1,2-bis(2-chloroethoxy)ethane and diethylene glycol bis(2-chloroethyl) ether; (3) The diepoxy compound includes one or more of 1,4-butanediol diglycidyl ether, 1,2-ethylenediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,2-propylenediol diglycidyl ether, 1,10-decanediol diglycidyl ether, 1,2,5,6-diepoxyhexane and 1,2,7,8-diepoxyoctane.

6. The leveling agent according to claim 5, characterized in that The molar ratio of the cyclic secondary amine compound or its salt, the dihalogenated alkyl ether and the diepoxide compound is 1:(0.1-0.7):(0.1-1.5).

7. The leveling agent according to any one of claims 1 to 4, characterized in that The number average molecular weight of the effective ingredient is 500-20000.

8. A method for preparing a leveling agent according to any one of claims 1 to 7, characterized in that: The following steps are involved: A cyclic secondary amine compound or a salt thereof and a dihalogenated alkyl ether are subjected to a nucleophilic substitution reaction to obtain an intermediate; The intermediate and the diepoxy compound are subjected to a ring-opening polymerization reaction to obtain the leveling agent.

9. A copper electroplating solution, characterized in that A leveling agent comprising any one of claims 1 to 7, or a leveling agent prepared by the method for preparing the leveling agent according to claim 8; The concentration of the leveler in the copper electroplating solution is 5ppm-1000ppm.

10. A copper electroplating method, characterized in that: The following steps are involved: The copper electroplating solution as claimed in claim 9 is used to electroplate a substrate to form a copper plating layer.

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