CN116024558A

CN116024558A - Efficient complexing chemical copper plating solution and preparation method thereof

Info

Publication number: CN116024558A
Application number: CN202211681025.3A
Authority: CN
Inventors: 孙宇曦; 董美敬; 曾庆明
Original assignee: Guangdong Shuocheng Technology Co ltd
Current assignee: Guangdong Shuocheng Technology Co ltd
Priority date: 2022-12-26
Filing date: 2022-12-26
Publication date: 2023-04-28

Abstract

The application provides a high-efficient complex formula electroless copper plating solution, the component of copper plating solution includes: a copper source, a nickel source, an organic matter with at least one N heterocycle, a complexing agent, an accelerator, a reducing agent, a surfactant and a pH regulator; the organic matter with at least one N heterocycle is selected from any one or a combination of a plurality of phenanthroline, imidazole, pyridine and bipyridine; the copper plating solution can produce a coordination effect with copper ions and complex with reaction byproducts through the synergistic effect of the components, so that the copper plating solution has excellent stability and high activity, can prepare a copper plating layer with high thickness and high plating speed at a lower temperature, and has obviously improved copper plating rate and excellent copper plating performance.

Description

Efficient complexing chemical copper plating solution and preparation method thereof

Technical Field

The invention relates to the technical field of C23C, in particular to a high-efficiency complexing electroless copper plating solution and a preparation method thereof.

Background

Electroless copper plating is a copper plating method of a PCB circuit board, and electroless plating solution mainly comprises copper salt, reducing agent, complexing agent, stabilizer, pH regulator and the like; in the copper plating reaction, besides the reduction of copper ions into elemental copper, a plurality of side reactions, including Kangni's reaction and non-catalytic reaction, exist, copper ions can react to generate elemental copper and copper ions in the process, and the side reaction products of the copper ions are distributed in the electroplating solution, so that the stability of the electroplating solution can be obviously reduced, the electroplating solution is decomposed, and the copper plating layer is loose and coarse, has poor binding force with a substrate and other adverse phenomena. Therefore, how to stabilize the copper plating solution, improve the copper plating efficiency and the copper plating quality is a major problem to be solved in the present application.

Chinese patent CN102191491a discloses an electroless copper plating solution and an electroless copper plating method, in which the stability of the copper plating solution is effectively improved by using a stabilizer N-methylmorpholine, but the copper plating solution can achieve a thick plating effect only at a working temperature of 30-50 ℃, the activity of the copper plating solution is insufficient, and the copper plating efficiency is low. Chinese patent CN114540889a discloses a copper plating additive, copper plating solution and application thereof, so as to solve the defects of uneven plating layer and insufficient bright appearance of the plating layer of cyanide-free brush copper plating, but the technology cannot realize high-speed and high-thickness copper plating, and the copper plating solution cannot adapt to different electroplating matrixes, and has a narrow application range.

Disclosure of Invention

In order to solve the technical problems, the invention firstly provides a high-efficiency complexing electroless copper plating solution, which comprises the following components: copper source, nickel source, organic matter with at least one N heterocycle, complexing agent, accelerator, reducer, surfactant and pH regulator.

Further, the copper source is Cu ²⁺ Selected from the group consisting of, but not limited to, copper sulfate pentahydrate, copper chloride, copper nitrate, basic copper carbonate, copper sulfamate, and combinations of one or more thereof.

Further, the concentration of the copper source in the copper plating solution is 4 to 15g/L, preferably 5 to 12g/L.

Further, the nickel source is Ni ²⁺ Including but not limited to one or more of nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel nitrate, nickel acetate, nickel carbonate, nickel sulfamate.

Further, the concentration of the nickel source in the copper plating solution is 0.05 to 1g/L, preferably 0.1 to 0.5g/L.

Further, the organic matter having at least one N-heterocyclic ring is selected from any one or a combination of several of phenanthroline, imidazole, pyridine and bipyridine.

Further, the phenanthroline has the following structure:

wherein R is ₁ And R is ₂ Any one selected from C0-C20 alkyl with polar groups or salts thereof; the polar group includes any one or a combination of a plurality of amino groups, primary amino groups, secondary amino groups, tertiary amino groups, hydroxyl groups, ether bonds, carboxyl groups and mercapto groups.

Further, the imidazoles have the following structure:

wherein said R is ₃ 、R ₄ And R is ₅ Any one or a combination of several of C1-C20 alkyl, -H, phenyl and polar groups.

Further, the bipyridines have the following structure:

wherein the R is ₆ And R is ₇ Is any one or more of C1-C18 alkyl, C0-C15 alkyl containing at least one of O, N, S.

In a preferred embodiment, the organic compound having at least one N-heterocyclic ring is bipyridyl.

Further, the bipyridines include, but are not limited to, 1-bis (4-carboxy-benzylidene) -4, 4-bipyridine dichloride

Ethyl viologen dibromide

Dibromide-1, 1-bis (3, 4-dicarboxy-benzylidene) -4,4 bipyridine +.>

1,1' -bis (2, 4-dinitrophenyl)) -4,4' -bipyridine dichloride->

At least one of them.

Preferably, the bipyridines are selected from any one of 1, 1-bis (4-carboxy-benzylidene) -4, 4-bipyridine, ethyl viologen dibromide, 1-bis (3, 4-dicarboxy-benzylidene) -4, 4-bipyridine, 1 '-bis (2, 4-dinitrophenyl) -4,4' -bipyridine dichloride.

Further, the concentration of the organic matter with at least one N heterocycle in the copper plating solution is 0.003-0.1g/L; preferably 0.003-0.05g/L.

The application finds that: when the organic matter with at least one N heterocycle is 1,1 '-bis (2, 4-dinitrophenyl) -4,4' -bipyridine dichloride, the concentration of the organic matter in the copper plating solution is 0.005-0.02g/L, the electroplating solution system has optimal stability, the surface porosity of the copper plating layer is low, the copper plating layer is more uniform, and the analysis of the applicant is that: the N group in the pyridine substance can generate coordination with copper ions in the copper plating solution to form a complex, when the carboxyl and the phenyl are grafted outside the pyridine group, the generated pi electron conjugation enhances the coordination of the pyridine group to the copper ions, the stability coefficient of the complex is higher, the coordination enables the copper ions to be well dispersed in the system to further influence the growth process of copper grains, copper plating particles are changed into a bulk shape from cones, and the plating layer is more uniform and compact; however, when the coordination is too strong or the addition amount of 1,1 '-bis (2, 4-dinitrophenyl) -4,4' -bipyridine dichloride is too large, the fixation effect on copper ions in the plating solution is too strong, but the electrochemical deposition of copper ions on the surface is passivated, so that the electroplating rate is reduced.

Further, the complexing agent includes, but is not limited to, citric acid, potassium sodium tartrate, sodium salicylate, sodium ethylenediamine tetraacetic acid, nitriloacetic acid and alkali metal salts thereof, gluconic acid, gluconate, triethanolamine, tetrahydroxypropylethylenediamine, modified ethylenediamine tetraacetic acid, phenylethylenediamine tetraacetic acid, S-ethylenediamine disuccinic acid, and combinations of one or more thereof.

Further, the complexing agent is at least one selected from potassium sodium tartrate, sodium salicylate, ethylenediamine tetraacetic acid sodium salt, tetrahydroxypropyl ethylenediamine and phenyl ethylenediamine tetraacetic acid.

In a preferred embodiment, the complexing agents are potassium sodium tartrate and tetra sodium ethylene diamine tetraacetate.

Further, the mass ratio of potassium sodium tartrate to tetra sodium ethylenediamine tetraacetate is (2-8): 1, a step of; preferably (3-6): 1.

further, the concentration of the complexing agent in the copper plating solution is 15-35g/L, preferably 20-30g/L.

Further, the accelerator is selected from any one or a combination of a plurality of sulfonate, carboxylate, thiazole, thiophene, diamine or polyamine and potassium ferrocyanide.

Further, the sulfonate includes, but is not limited to, any one of C2-C15 alkylbenzene sulfonate, alkyl diphenyl ether disulfonic acid, sodium acyl methylamine alkane sulfonate, p-toluene sulfonate, and mercapto alkyl sulfonate.

Further, the carboxylate includes, but is not limited to, at least one of 4-pyrimidinecarboxylic acid and its salts, 5-chloropyrimidine-4-carboxylate.

Further, the thiazoles include, but are not limited to, at least one of 2-mercaptobenzothiazole and salts thereof, 2' -dithiodibenzothiazole and salts thereof.

Further, the thiophenes include, but are not limited to, at least one of C1-12 alkyl thiophenes and salts thereof, thiophene diformate, benzodithiophene and salts thereof.

Further, the di-or polyamines include, but are not limited to, at least one of tetrahydroxypropyl ethylenediamine, triethanolamine.

Preferably, the accelerator is a combination of a diamine or polyamine and potassium ferrocyanide, more preferably a combination of tetrahydroxypropyl ethylenediamine and potassium ferrocyanide.

Further, the mass ratio of the tetrahydroxypropyl ethylenediamine to the potassium ferrocyanide in the accelerator is (1-5): 2; preferably (1.5-4.5): 2.

further, the concentration of the accelerator in the copper plating solution is 0.04-0.5g/L, preferably 0.08-0.3g/L.

Further, the reducing agent includes, but is not limited to, formaldehyde precursors, formaldehyde derivatives, glyoxylic acid derivatives, borohydrides, borohydride substituents, boranes, dimethylamine borane (DMAB), hypophosphorous acid, glyoxylic acid, combinations of one or more thereof.

Preferably, the reducing agent is formaldehyde.

In some embodiments, the concentration of the reducing agent in the copper plating solution is 2 to 9g/L, preferably 2 to 5g/L.

Further, the surfactant is one or more selected from polyvinylpyrrolidone, polyethylene glycol, cetyl polyoxypropylene polyoxyethylene ether, nonylphenol polyoxyethylene ether, octylphenol polyoxyethylene ether and nonionic polyacrylamide.

Further, the polyethylene glycol includes, but is not limited to, PEG500, PEG600, PEG800, PEG1000, PEG1200, PEG1500, PEG2000; preferably any one or a combination of a plurality of PEG1000, PEG1200 and PEG 1500.

Further, the polyvinylpyrrolidone has a number average molecular weight of 5000 to 150000; preferably 8000 to 130000;

the application surprisingly finds that: when the surfactant is polyvinylpyrrolidone and the number average molecular weight thereof is further defined as 10000 to 50000, the copper plating rate and copper plating quality can be further improved, and the applicant speculates that the reason is that: the polyvinylpyrrolidone has a large number of polar groups on the surface and a longer molecular chain, and a cross-linking structure formed by the molecular chain in the system can disperse and coat copper ions and copper grains, so that the grain size is obviously refined and the uniformity of the grains is improved, but the special structure of the polyvinylpyrrolidone can generate hydrogen bond action and molecular chain entanglement with complexing agents such as potassium sodium tartrate and tetra sodium ethylenediamine tetraacetate, stabilizers and accelerators in the system to influence the dispersion of the copper ions and the grains, when the number average molecular weight of the polyvinylpyrrolidone is too large, the internal cross-linking action is too strong, not only can directly influence the coordination and complexation of the stabilizer and the complexing agent on the copper ions, but also obviously slow down the deposition speed of the copper ions, and when the number average molecular weight of the polyvinylpyrrolidone is too small, the dispersion action on the copper ions and the grains is low, and the compactness and uniformity of the grains are reduced.

Further, the concentration of the surfactant in the copper plating solution is 0.0005-0.01g/L.

Further, the pH adjuster includes, but is not limited to, at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium borohydride.

Further, the working temperature of the copper plating solution is 30-35 ℃, preferably 33-35 ℃; the pH of the copper plating solution is 11 to 13, preferably 12 to 13.

Secondly, the application also provides a preparation method of the copper plating solution: mixing a complexing agent, a pH regulator and water, and marking as A solution; sequentially mixing a copper source, a nickel source and a reducing agent, and marking as liquid B; sequentially adding a surfactant, an accelerator and an organic matter with at least one N heterocycle into water, mixing and marking as a C solution; and finally, sequentially mixing the solution A, the solution B and the solution C and adjusting the pH value of the copper plating solution.

Further, the copper plating substrate of the copper plating solution is not strictly limited, and materials with different Tg can be selected for copper plating, wherein the substrate comprises, but is not limited to, high Tg (S1000-2M) and medium Tg (S1000) type plates of Guangdong life and technology Co., ltd; high Tg (halogen-free IT-958G) and medium Tg (halogen-free IT 150G) type plates of the Lien electronic Co Ltd; any one of high Tg (leadless NY7350 ANT) and PTFE high frequency material (NYHP-255D) of Nanya New Material technologies Co., ltd.

Further, the copper plating method of the copper plating solution includes the steps of:

s1, treating a substrate, wherein the substrate comprises the following steps: bulking, removing gel, pre-neutralizing, pore-forming, activating and reducing;

s2, placing the treated base material into copper plating solution with the pH value of 11-13 at the temperature of 30-35 ℃ for copper precipitation.

Further, in the step S2, the temperature is preferably 32-35 ℃, and the pH is preferably 12-13.

Advantageous effects

1. The copper plating solution can produce a coordination effect with copper ions and complex with reaction byproducts through the synergistic effect of the components, so that the copper plating solution has excellent stability, a copper plating layer with high thickness and high plating speed can be prepared, the copper plating rate is obviously improved, and the copper plating layer has excellent performance;

2. the electroplating solution can be matched with substrates of different materials by optimizing the component proportions and the consumption of the complexing agent, the stabilizer and the accelerator, and has wide application range to the substrates, excellent adhesive force and high plating reliability and yield;

3. the copper plating solution has high copper plating activity, and can be used for carrying out a copper plating process with high thickness, high speed, high quality and high efficiency at the temperature of 30-35 ℃, compared with the traditional process, the heat energy consumption is effectively saved, the raw material consumption with higher cost is also reduced, and the process cost is effectively reduced.

Drawings

Fig. 1-10: backlight patterns of copper plating layers of copper plating solutions of examples 1 to 6 and comparative examples 1 to 6 on S1000-2M type substrates were shown in this order;

fig. 11-20: backlight patterns of copper plating layers of copper plating solutions of examples 1 to 6 and comparative examples 1 to 6 on IT-150G type substrates are shown in order;

fig. 21-30: backlight patterns of copper plating layers of copper plating solutions of examples 1 to 6 and comparative examples 1 to 6 on NYHP-225D type substrates were shown in this order.

Detailed Description

Examples

Example 1

The embodiment provides a high-efficiency complexing chemical copper plating solution, which comprises the following components: 8g/L of copper sulfate, 0.3g/L of nickel sulfate, 0.01g/L of 1,1 '-bis (2, 4-dinitrophenyl) -4,4' -bipyridine dichloride, 20g/L of potassium sodium tartrate, 5g/L of tetrasodium ethylenediamine tetraacetate, 0.04g/L of potassium ferrocyanide, 0.06g/L of tetrahydroxypropyl ethylenediamine, 11mL/L of 37wt% formaldehyde solution, 0.001g/L of polyvinylpyrrolidone (number average molecular weight 20000), 13g/L of sodium hydroxide and water;

the preparation method of the copper plating solution comprises the following steps:

sequentially adding corresponding amounts of potassium sodium tartrate, tetra sodium ethylenediamine tetraacetate and sodium hydroxide into a beaker, adding 500mL of distilled water for dissolution, and marking as A solution; sequentially adding corresponding amounts of copper sulfate pentahydrate and nickel sulfate hexahydrate into a beaker, adding 50mL of distilled water for dissolution and mixing, and adding 11mL of 37wt% formaldehyde solution to obtain solution B; then taking a beaker, sequentially adding relative amounts of polyvinylpyrrolidone, potassium ferrocyanide, tetrahydroxypropyl ethylenediamine and 1,1 '-bis (2, 4-dinitrophenyl) -4,4' -bipyridine dichloride, adding 200mL of distilled water for dissolution, and recording as a C solution. Mixing the solution A, the solution B and the solution C in sequence, fixing the volume to 1L by using distilled water, and adjusting the copper plating solution to 13 by using a pH meter.

Example 2

This example corresponds to example 1, with the difference that: the 1,1 '-bis (2, 4-dinitrophenyl) -4,4' -bipyridine dichloride is 0.005g/L.

Example 3

This example corresponds to example 1, with the difference that: the 1,1 '-bis (2, 4-dinitrophenyl) -4,4' -bipyridine dichloride is 0.015g/L.

Example 4

This example corresponds to example 1, with the difference that: the 1,1 '-bis (2, 4-dinitrophenyl) -4,4' -bipyridine dichloride is 0.02g/L.

Example 5

This example corresponds to example 1, with the difference that: the tetrahydroxypropyl ethylenediamine is 0.03g/L.

Example 6

This example corresponds to example 1, with the difference that: the tetrahydroxypropyl ethylenediamine is 0.09g/L.

Comparative example 1

Substantially identical to example 1, except that: no tetrasodium ethylenediamine tetraacetate was added.

Comparative example 2

Substantially identical to example 1, except that: no nickel sulfate hexahydrate was added.

Comparative example 3

Substantially identical to example 1, except that: replacing the 1,1' -bis (2, 4-dinitrophenyl) -4,4' -bipyridine with 2,2' -bipyridine;

sequentially adding corresponding amounts of potassium sodium tartrate, tetra sodium ethylenediamine tetraacetate and sodium hydroxide into a beaker, adding 500mL of distilled water for dissolution, and marking as A solution; sequentially adding a corresponding amount of copper sulfate pentahydrate and 50mL of distilled water into a beaker to dissolve and mix, dissolving nickel sulfate hexahydrate with 50mL of distilled water, mixing the two, and then adding 11mL of 37wt% formaldehyde solution to obtain solution B; then taking one beaker, sequentially adding relative amounts of polyvinylpyrrolidone, potassium ferrocyanide and tetrahydroxypropyl ethylenediamine, adding 200mL of distilled water for dissolution, sequentially adding 1mL of methanol, 2' -bipyridine and 10mL of distilled water into the other beaker for dissolution, mixing the two, and recording as a C solution. Mixing the solution A, the solution B and the solution C in sequence, fixing the volume to 1L by using distilled water, and adjusting the copper plating solution to 13 by using a pH meter.

Comparative example 4

Substantially identical to example 1, except that: replacing the 1,1 '-bis (2, 4-dinitrophenyl) -4,4' -bipyridine dichloride with 2-mercaptobenzothiazole;

sequentially adding corresponding amounts of potassium sodium tartrate, tetra sodium ethylenediamine tetraacetate and sodium hydroxide into a beaker, adding 500mL of distilled water for dissolution, and marking as A solution; sequentially adding a corresponding amount of copper sulfate pentahydrate and 50mL of distilled water into a beaker to dissolve and mix, dissolving nickel sulfate hexahydrate with 50mL of distilled water, mixing the two, and then adding 11mL of 37wt% formaldehyde solution to obtain solution B; sequentially adding relative amounts of polyvinylpyrrolidone, potassium ferrocyanide and tetrahydroxypropyl ethylenediamine into a beaker, adding 200mL of distilled water for dissolution, sequentially adding 1mL of 32wt% NaOH, 2-mercaptobenzothiazole into the beaker, and dissolving with 10mL of distilled water; the mixture of the two is denoted as liquid C. Mixing the solution A, the solution B and the solution C in sequence, fixing the volume to 1L by using distilled water, and adjusting the copper plating solution to 13 by using a pH meter.

Comparative example 5

Substantially identical to example 1, except that: the 1,1 '-bis (2, 4-dinitrophenyl) -4,4' -bipyridine dichloride was replaced with ethyl viologen dibromide.

Comparative example 6

Substantially identical to example 1, except that: the number average molecular weight of the polyvinylpyrrolidone was 60000.

The performance test method comprises the following steps:

1. pretreatment and electroless copper plating process:

the chemical copper solutions described in the examples were copper plated using three different types of substrates, high Tg (S1000-2M), medium Tg (halogen free IT 150G) and PTFE high frequency material (NYHP-225D), and the substrates were processed as follows:

(1) Swelling the substrate with a swelling agent (amides, SCC-A01H, manufactured by Guangdong Co., ltd.) at 80deg.C for 6min; then washing the substrate with tap water at room temperature for 1min, and washing with distilled water for 1min

(2) Removing colloid (SCC-A02, guangdong Co., ltd.) at 80deg.C for 12min, wherein the colloid is sodium permanganate system, and aims to oxidize and dissolve colloid residue to generate roughness on the surface of the medium; then washing the substrate with tap water for 1min at room temperature, and washing with distilled water for 1min;

(3) Using H ₂ SO ₄ And H ₂ O ₂ Ultrasonic processing is carried out on the system for 2min at room temperature, so as to remove residual liquid after removing the gumming residues on the attached substrate; then washing the substrate with tap water for 1min at room temperature, and washing with distilled water for 1min;

(4) Neutralizing with an organic neutralizing agent (SCC-A03H, manufactured by Guangdong Co., ltd.) at 50deg.C for 40s; then washing the substrate with tap water for 1min at room temperature, and washing with distilled water for 1min;

(5) Conditioning treatment with conditioning agent (SCC-A04H 3, manufactured by Guangdong Co., ltd.) at 50deg.C for 1min, with the aim of cleaning copper and further conditioning the glass filaments in the pores; then washing the substrate with tap water for 1min at room temperature, and washing with distilled water for 1min;

(6) Treating with a mixed solution of 80g/L sodium persulfate and 8wt% sulfuric acid (the volume ratio of the two is 1:1) at room temperature for 1min;

(7) Treating with prepreg (SCC-A05 LP, guangdong Co., ltd.) at 45deg.C for 20S, and treating with activating solution (SCC-A06H, guangdong Co., ltd.) at 45deg.C for 45S, to attach metal activator on the surface and wall of the substrate, and enhancing activity; then washing the substrate with tap water at room temperature for 1min, and washing with distilled water for 1min

(8) Treatment with a reducing agent (SCC-A07H, guangdong Co., ltd.) at 35℃for 35s, the purpose of which is to reduce palladium ions to palladium atoms, and to catalyze the copper plating process;

(9) Electroless copper plating was performed at 33℃for 15min using the electroless copper plating solutions in examples 1 to 10, respectively.

2. Copper deposition rate performance evaluation:

after the electroless copper plating process is completed, the copper deposition rate of the substrate is calculated according to the following formula:

v is the thickness of copper deposit, and the unit is mu m; m1 and M2 are mass before copper deposition and mass after copper deposition respectively, and the unit is g; ρ is the density of copper, 8.9g/cm ³ The method comprises the steps of carrying out a first treatment on the surface of the S is the surface area of the plate in cm ² 。

3. Backlight grade performance evaluation:

a plurality of 1mm thick side sections were selected from the hole walls cut from each plate, and the sections of each substrate were observed under a metallographic optical microscope at a magnification of 50X. The quality of the deposited copper film was determined under a microscope by means of illumination and the thickness of the walls of the through-holes was determined using a European backlight grading table. The backlight values show the effect of the reducing composition of the present invention on the backlight.

The backlight grade discrimination criteria are: stage 1: the light transmission area is more than 90%;2 stages: light transmission, 80% < light transmission area less than or equal to 90%;3 stages: light transmission, 70% < light transmission area less than or equal to 80%;4 stages: light transmission, 60% < light transmission area less than or equal to 70%;5 stages: light transmission, 50% < light transmission area less than or equal to 60%; stage 6: dark light, 40% < visible light area less than or equal to 50%, clear fiber shape; 7 stages: dark light, 30% < visible light area less than or equal to 40%, the dark light is fibrous; 8 stages: dark light, 20% < visible light area less than or equal to 30%, part of the dark light is initially fibrous; 8.5 grade: dark light, 10% < visible light area less than or equal to 20%, and the dark light is distributed in a scattered form of 10 points; stage 9: dark light, wherein the visible light area is less than or equal to 10 percent and the dark light is distributed in a scattered form of < 5; grade 9.5: dark light, 1% < visible light area less than or equal to 5%, and the dark light is distributed in a scattered form of starting from <2 points; 10 grades: and (3) completely black.

4. Electroless copper plating solution stability assessment

The electroless copper plating solutions obtained in the examples were placed in beakers, respectively, 20mL of a palladium chloride solution having a concentration of 0.18g/L was added per 100mL of the electroless copper plating solution to perform a catalytic decomposition reaction, and the decomposition starting time was recorded.

Performance test results:

the test results are shown in Table 1.

TABLE 1

TABLE 3 Table 3

Claims

1. The efficient complexing type electroless copper plating solution is characterized by comprising the following components: a copper source, a nickel source, an organic matter with at least one N heterocycle, a complexing agent, an accelerator, a reducing agent, a surfactant and a pH regulator;

the organic matter with at least one N heterocycle is selected from any one or a combination of a plurality of phenanthroline, imidazole, pyridine and bipyridine.

2. The electroless copper plating solution according to claim 1, wherein the phenanthroline group has the following structure:

wherein R is ₁ And R is ₂ Any one selected from C0-C20 alkyl with polar groups or salts thereof; the polar group comprises any one or a combination of a plurality of amino, primary amino, secondary amino, tertiary amino, hydroxyl, ether bond, carboxyl and sulfhydryl.

3. The electroless copper plating solution according to claim 1, wherein the bipyridyl has the following structure:

4. The electroless copper plating solution according to claim 3, wherein the bipyridyl is selected from any one of 1, 1-bis (4-carboxy-benzylidene) -4, 4-bipyridyl dichloride, ethyl viologen dibromide, 1-bis (3, 4-dicarboxy-benzylidene) -4, 4-bipyridine, 1 '-bis (2, 4-dinitrophenyl) -4,4' -bipyridine dichloride.

5. The electroless copper plating solution according to claim 1, wherein the concentration of the organic substance having at least one N-heterocycle in the copper plating solution is 0.003 to 0.1g/L.

6. The electroless copper plating solution according to claim 1, wherein the complexing agent is at least one selected from the group consisting of potassium sodium tartrate, sodium salicylate, ethylenediamine tetraacetic acid sodium salt, tetrahydroxypropyl ethylenediamine, and phenyl ethylenediamine tetraacetic acid, and the concentration of the complexing agent in the copper plating solution is 15-35g/L.

7. The electroless copper plating solution according to claim 1, wherein the accelerator is selected from any one or a combination of a plurality of sulfonate, carboxylate, thiazole, thiophene, diamine or polyamine, and potassium ferrocyanide, and the concentration of the accelerator in the copper plating solution is 0.04-0.5g/L.

8. The electroless copper plating solution according to claim 1, wherein the surfactant is polyvinylpyrrolidone.

9. The electroless copper plating solution according to claim 8, wherein the copper plating solution has an operating temperature of 30-35 ℃.

10. The method for producing an electroless copper plating solution according to any one of claims 1 to 9, characterized in that the production method is: mixing a complexing agent, a pH regulator and water, and marking as A solution; sequentially mixing a copper source, a nickel source and a reducing agent, and marking as liquid B; sequentially adding a surfactant, an accelerator and an organic matter with at least one N heterocycle into water, mixing and marking as a C solution; and finally, sequentially mixing the solution A, the solution B and the solution C and adjusting the pH value of the copper plating solution.