A kind of oil removal liquid for uniform electroless copper plating on non-conductive substrate of printed circuit board

Abstract

The application discloses a kind of printed circuit board non-conductive base material uniform chemical plating copper oil removal liquid, belong to oil removal liquid technical field.The oil removal liquid includes ethanolamine, diethanolamine, mixed quaternary amine salt, nonylphenol polyoxyethylene ether, polyethylene glycol 1000, the oil removal liquid prepared not only can be carried out charge adjustment on the normal roughness non-conductive base material wall, can also be carried out charge adjustment on the non-conductive base material of the problem such as the roughness of hole wall too large, glass fiber protrusion caused by poor drilling, and can uniformly adsorb palladium in subsequent micro-etching, pre-impregnation, activation, acceleration, copper deposition and other operations, then form uniform fine plating layer in chemical copper plating solution, so that the treated circuit board substrate has the advantages of uniform plating layer, copper layer is not easy to peel off at peeling fiber, and rough wall can uniformly adhere copper layer, and the method for preparing the oil removal liquid is simple, low in cost, strong in operability, suitable for mass production.

Description

A degreasing solution for uniform chemical copper plating on non-conductive substrates of printed circuit boards Technical Field

[0001] This invention relates to the field of degreasing liquid technology, specifically to a degreasing liquid for uniformly chemically plating copper onto non-conductive substrates of printed circuit boards. Background Technology

[0002] Printed circuit boards (PCBs) are important electronic components. In recent years, with the advancement of technology and the development of the electronics industry, as well as the refinement and efficiency of electronic devices, the multi-layering of PCB wiring and the miniaturization of interlayer vias have placed increasingly higher demands on PCB manufacturing capabilities. This necessitates uniform and reliable chemical copper plating during via metallization.

[0003] Currently, PCB hole metallization is generally achieved through chemical copper plating. However, the first-pass yield rate in China is lower than that abroad. This is mainly because China does not pay much attention to pre-plating treatment, especially the degreasing stage. This stage has been studied less because it does not have added value. Research on PCB hole metallization technology is still mainly focused on chemical copper plating and colloidal palladium activation stages. However, the degreasing stage plays a crucial role in ensuring the uniform adsorption of the catalytic palladium layer and the electroless copper plating layer. In the colloidal palladium electroless copper plating process, the printed circuit board must first undergo degreasing to adjust the charge, ensuring that the hole wall charge is adjusted to a positive state. This lays the foundation for the subsequent adsorption of negatively charged colloidal palladium particles and also cleans the surface of the circuit board and the copper layer in the holes. However, the hole walls in the circuit board inevitably suffer from excessive roughness and glass fiber protrusion due to the dulling of the drill bit during the drilling process. Moreover, as the hole diameter decreases, the roughness has a significant impact on the uniformity of copper plating within the circuit board holes. Uneven copper plating can easily lead to negative impacts on signal transmission and circuit performance, weakening and reducing signal transmission, especially in high-frequency applications. It can also reduce the strength and reliability of connection points, thus affecting the normal operation of the overall circuit. In addition, glass fiber protrusions on the hole walls may cause uneven accumulation of plating solution on the hole walls, resulting in uneven plating layer thickness and reduced quality. It may also lead to defects such as thickness differences, cracks, and holes, affecting the application of the printed circuit board.

[0004] Therefore, there is an urgent need for a new type of degreasing solution that can uniformly chemically plate copper, so as to ensure that even if there are problems such as rough hole walls or protruding glass fibers in the circuit board holes, the chemical copper layer can be uniformly covered. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an oil-removing solution that can be used on non-conductive substrates of printed circuit boards and achieve uniform chemical copper plating. This ensures that even when the hole wall roughness is relatively large, a good chemical plating effect can be obtained in the circuit board holes, thereby improving the quality of hole metallization.

[0006] To achieve the above objectives, the present invention provides the following technical solution to address the technical problem:

[0007] On one hand, the present invention provides a degreasing solution for uniformly electroless copper plating on non-conductive substrates of printed circuit boards. The degreasing solution comprises 1-4 g / L ethanolamine, 4-7 g / L diethanolamine, 0.1-25 g / L mixed quaternary ammonium salt, 2-7 g / L nonylphenol polyoxyethylene ether, and 0.5-3 g / L polyethylene glycol 1000. The mixed quaternary ammonium salt comprises compound one with the structural formula shown in formula (I) and compound two with the structural formula shown in formula (II).

[0008] (I)

[0009] In equation (I), n = 1 to 7;

[0010] (II).

[0011] Preferably, the degreasing solution comprises 1.5–3.5 g / L ethanolamine, 4.5–6.5 g / L diethanolamine, 0.2–20 g / L mixed quaternary ammonium salt, 4–5 g / L nonylphenol polyoxyethylene ether, and 1–2 g / L polyethylene glycol 1000.

[0012] More preferably, the degreasing solution comprises 2.5 g / L ethanolamine, 5 g / L diethanolamine, 5 g / L mixed quaternary ammonium salt, 4.5 g / L nonylphenol polyoxyethylene ether, and 1.5 g / L polyethylene glycol 1000.

[0013] Preferably, the mass ratio of compound one to compound two is (1-20):1.

[0014] More preferably, the mass ratio of compound one to compound two is 1:1.

[0015] The amount of compound one used in the mixed quaternary ammonium salt ranges from 0.1 to 20 g / L, and the amount of compound two used ranges from 0.05 to 10 g / L.

[0016] On the other hand, the present invention also provides a method for preparing the degreasing solution for uniform chemical copper plating on a non-conductive substrate of a printed circuit board, the preparation method comprising the following steps:

[0017] S1. Under the catalysis of an alkali, triethanolamine and anhydrous ethanol were mixed and heated to 65°C to 80°C. Then, raw material A was added and reacted for 4 to 6 hours. After separation and purification, compound one was obtained.

[0018] S2. Under the catalysis of an alkali, triethanolamine and anhydrous ethanol were mixed and heated to 65°C to 80°C. Then, raw material B was added and reacted for 4 to 6 hours. After separation and purification, compound II was obtained.

[0019] S3. Mixing compound 1 and compound 2 to prepare a mixed quaternary ammonium salt;

[0020] S4. Ethanolamine, diethanolamine, nonylphenol polyoxyethylene ether, polyethylene glycol 1000, and mixed quaternary ammonium salts are added to deionized water and mixed to prepare an oil-removing solution.

[0021] Preferably, in step S1, raw material A is added in 10 batches, with each batch spaced 2 hours apart.

[0022] Preferably, the raw material A is a dihaloalkyl ether, and its structural formula is shown in formula (Ⅲ) below:

[0023] (III)

[0024] In formula (Ⅲ), n = 1 to 7; X is a halogen atom.

[0025] More preferably, the raw material A is selected from one of dichlorodiethyl ether, 1,2-di(2-chloroethoxy)ethane, or diethylene glycol bis(2-chloroethyl) ether.

[0026] Preferably, raw material B is 1,4-dichlorobenzyl.

[0027] In addition, the present invention also provides the application of the degreasing solution for uniform electroless copper plating of non-conductive substrates of printed circuit boards or the degreasing solution prepared by the preparation method according to any one of claims 6 to 9 in the degreasing process of electroless copper plating of printed circuit boards.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] This invention provides a novel degreasing solution for non-conductive substrates of printed circuit boards, enabling uniform electroless copper plating. The degreasing solution comprises ethanolamine, diethanolamine, a mixed quaternary ammonium salt, nonylphenol polyoxyethylene ether, and polyethylene glycol 1000. The mixed quaternary ammonium salt is composed of compound one with the structure shown in formula (I) and compound two with the structure shown in formula (II). Compared to existing degreasing solutions, the degreasing solution of this invention can adjust the charge on non-conductive substrate walls with normal roughness, as well as on non-conductive substrates with excessive hole wall roughness or fiberglass protrusion caused by poor drilling. Furthermore, it uniformly adsorbs palladium in subsequent processes, thereby forming a uniform and fine plating layer in the electroless copper plating solution, achieving excellent electroless plating results and improving product quality.

[0030] Furthermore, this invention also provides a method for preparing the degreasing solution, which is simple to operate, highly operable, and low in cost, making it suitable for large-scale industrial production. It also expands the types of degreasing solutions available, which is beneficial to the development of chemical copper plating processes. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to specific examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; the materials and reagents used are commercially available unless otherwise specified.

[0033] The structures of compound 1 and compound 2 involved in the following examples of the present invention are shown below:

[0034] Compound 1: (I)

[0035] In equation (I), n = 1 to 7;

[0036] Compound 2: (II).

[0037] Example 1

[0038] A degreasing solution for uniformly electroless copper plating on non-conductive substrates of printed circuit boards, the degreasing solution comprising ethanolamine, diethanolamine, mixed quaternary ammonium salts, nonylphenol polyoxyethylene ether, and polyethylene glycol 1000. The preparation method of the degreasing solution specifically includes the following steps:

[0039] I. Preparation of Compound I

[0040] 1. Add 0.1 mol of triethanolamine and 150 ml of anhydrous ethanol to a 250 ml three-necked flask, then add 0.105 mol of NaOH. Place the three-necked flask in an oil bath, add a reflux apparatus, stir and heat to 77 °C. Then add 0.05 mol of dichlorodiethyl ether in 10 batches to the three-necked flask, with an interval of 2 h between each batch. After the addition is complete, continue the reaction for 5 h to obtain the crude compound.

[0041] 2. After the reaction is complete, the crude compound is cooled to room temperature, and then the solvent is evaporated under vacuum (vacuum degree is 0.08MPa) to obtain 26.27g of mixed crude product, which contains 0.05mol of compound one with the structure shown in formula (Ⅰ) (n=1). Compound one is 18.5g, with a mass content of 70.6%. The remainder is sodium chloride and a small amount of NaOH, which does not affect the product performance. The content is calculated when using it.

[0042] 1 H NMR (400MHz, D2O) δ: 4.34-4.14(m,6H), 3.97-3.92(m,12H), 3.85-3.73(m,4H), 3.45-3.38(m,16H).

[0043] II. Preparation of Compound II

[0044] 1. Add 0.1 mol of triethanolamine and 150 ml of anhydrous ethanol to a 250 ml three-necked flask, then add 0.105 mol of NaOH. Place the three-necked flask in an oil bath, add a reflux apparatus, stir and heat to 77 °C. Then add 0.05 mol of 1,4-dichlorobenzyl to the three-necked flask and continue the reaction for 5 h to obtain the crude compound.

[0045] 2. After the reaction is complete, the crude compound is cooled to room temperature, and then the solvent is evaporated under vacuum (vacuum degree is 0.08MPa) to obtain a white powder product. This white powder product does not need further purification. 27.87g of mixed crude product is obtained, which contains 0.05mol of compound II with the structure shown in formula (II). Compound II is 20.1g, with a mass content of 72%. The remainder is NaCl and a small amount of NaOH, which does not affect the product performance. The content is calculated when using it.

[0046] 1 H NMR (400MHz, D2O) δ: 7.19-7.08(m,4H), 4.55-4.48(m,4H), 4.28-4.19(m,6H), 3.99-3.88(m,12H), 3.45-3.39(m,12H).

[0047] III. Preparation of Degreasing Solution

[0048] Add 2.5g ethanolamine, 5g diethanolamine, 4.5g nonylphenol polyoxyethylene ether, 1.5g polyethylene glycol 1000, and 5g mixed quaternary ammonium salt [prepared from compound one and compound two in a 1:1 mass ratio] to 994ml deionized water, stir to dissolve, and obtain degreasing solution 1.

[0049] Example 2

[0050] The difference between Example 2 and Example 1 is that the preparation of compound 1 is different, but everything else is the same, thus obtaining degreasing liquid 2.

[0051] 1. Add 0.1 mol of triethanolamine and 150 ml of anhydrous ethanol to a 250 ml three-necked flask, then add 0.105 mol of NaOH. Place the three-necked flask in an oil bath, add a reflux apparatus, stir and heat to 77 degrees Celsius. Then add 0.05 mol of 1,2-bis(2-chloroethoxy)ethane to the three-necked flask in 10 batches, with an interval of 2 h between each batch. After the addition is complete, continue the reaction for 5 h. After the reaction is complete, the crude compound is obtained.

[0052] 2. Cool the crude compound to room temperature, and then evaporate the solvent under vacuum (vacuum degree is 0.08MPa) to obtain 28.47g of mixed crude product, which contains 0.05mol of compound one (n=2) with the structure shown in formula (Ⅰ). The mass content of compound one is 20.7g, which is 72.7%. The remainder is NaCl and a small amount of NaOH, which does not affect the product performance.

[0053] 1 H NMR (400MHz, D2O) δ: 4.29-4.13(m,6H), 3.97-3.92(m,12H), 3.85-3.73(m,4H), 3.55-3.48(m 4H), 3.45-3.38(m,16H).

[0054] Example 3

[0055] The difference between Example 3 and Example 1 is that the preparation of compound 1 is different, but everything else is the same, thus obtaining degreasing liquid 3.

[0056] 1. Add 0.1 mol of triethanolamine and 150 ml of anhydrous ethanol to a 250 ml three-necked flask, then add 0.105 mol of NaOH. Place the three-necked flask in an oil bath, add a reflux apparatus, stir and heat to 77 degrees Celsius. Then add 0.05 mol of diethylene glycol bis(2-chloroethyl) ether to the three-necked flask in 10 batches, with an interval of 2 hours between each batch. After the addition is complete, continue the reaction for 5 hours to obtain the crude compound.

[0057] 2. After the reaction is complete, the crude compound is cooled to room temperature, and then the solvent is evaporated under vacuum (vacuum degree is 0.08MPa) to obtain 30.67g of mixed crude product, which contains 0.05mol of compound one (n=3) with the structure shown in formula (Ⅰ). Compound one is 22.93g, with a mass content of 74.76%. The remainder is NaCl and a small amount of NaOH, which does not affect the product performance.

[0058] 1 H NMR (400MHz, D2O) δ: 4.31-4.11(m,6H), 3.96-3.92(m,12H), 3.84-3.71(m,4H), 3.53-3.46(m 8H), 3.45-3.38(m,16H).

[0059] Example 4

[0060] The difference between Example 4 and Example 1 is that the ratio of compound 1 and compound 2 in the mixed quaternary ammonium salt is different in the preparation of the degreasing solution, while everything else is the same, thus obtaining degreasing solution 4.

[0061] The mixed quaternary ammonium salt is prepared by compound one and compound two in a mass ratio of 4:1, specifically 4g of compound one and 1g of compound two.

[0062] Example 5

[0063] The difference between Example 5 and Example 1 is that the amount of the mixed quaternary ammonium salt used in the preparation of the degreasing solution is different, while everything else is the same, resulting in degreasing solution 5.

[0064] The amount of the mixed quaternary ammonium salt is 10g, which is prepared by compound one and compound two in a 1:1 mass ratio, specifically 5g of compound one and 5g of compound two.

[0065] Example 6

[0066] The difference between Example 6 and Example 1 is that the amount and ratio of the mixed quaternary ammonium salt are different in the preparation of the degreasing solution, while everything else is the same, resulting in degreasing solution 6.

[0067] The amount of the mixed quaternary ammonium salt is 10g, which is prepared by compound one and compound two in a mass ratio of 9:1, specifically 9g of compound one and 1g of compound two.

[0068] Example 7

[0069] The difference between Example 7 and Example 1 is that the amount and ratio of the mixed quaternary ammonium salt are different in the preparation of the degreasing solution, while everything else is the same, resulting in degreasing solution 7.

[0070] The amount of the mixed quaternary ammonium salt is 15g. The mixed quaternary ammonium salt is prepared by compound one and compound two in a mass ratio of 2:1, specifically 10g of compound one and 5g of compound two.

[0071] Example 8

[0072] The difference between Example 8 and Example 1 is that the amount and ratio of the mixed quaternary ammonium salt are different in the preparation of the degreasing solution, while everything else is the same, resulting in degreasing solution 8.

[0073] The amount of mixed quaternary ammonium salt used is 15g. The mixed quaternary ammonium salt is prepared by compound one and compound two in a 1:1 mass ratio, specifically 7.5g of compound one and 7.5g of compound two.

[0074] Comparative Example 1

[0075] The difference between Comparative Example 1 and Example 1 is that the composition of the degreasing solution is different. Comparative Example 1 uses commercially available cationic polyethyleneimine instead of the mixed quaternary ammonium salt in Example 1 to prepare the comparative degreasing solution.

[0076] Add 2.5g ethanolamine, 5g diethanolamine, 4.5g nonylphenol polyoxyethylene ether, 1.5g polyethylene glycol 1000, and 5g cationic polyethyleneimine (molecular weight 20,000) to 994ml of deionized water, stir to dissolve, and then prepare the degreasing solution.

[0077] Test Example 1

[0078] The performance of the degreasing solutions prepared in Examples 1-8 and Comparative Example 1 was tested for different hole wall roughnesses and glass fiber protrusions in printed circuit boards. First, holes were drilled in the printed circuit boards using a CNC drilling machine. The boards were categorized into seven types based on hole wall roughness (Table 2) or six types based on glass fiber protrusion (Table 3). Then, hole metallization was performed according to the following processes: swelling, desmearing, neutralization, degreasing, micro-etching, pre-dip, activation, acceleration, and copper plating. The coverage effect of different hole wall roughnesses or different glass fiber protrusions in the printed circuit boards was analyzed.

[0079] The reagents and operating parameters used in this test example were obtained from Guangdong Lier Chemical Co., Ltd. The swelling agent was EC-7Y, the desmearing agent was conventional sodium hydroxide and potassium permanganate, the neutralization agent was EC-9S, the degreasing solution was the degreasing solution used in Examples 1-8 and Comparative Example 1, the micro-etching agent was EC-32, the pre-impregnation agent was EC-33R, the activator was EC-34, and the electroless copper plating agent was EC-6. Specific operating parameters are shown in Table 1 below.

[0080] Table 1. Parameters for Adhesive Removal and Copper Plating

[0081]

[0082] Following the procedure in Table 1, a printed circuit board with metallized holes is obtained after copper plating. The board is then sliced ​​and its coverage effect is observed using a metallographic microscope. The coverage effect is recorded through backlight rating. The backlight is then compared for different hole wall roughnesses and fiberglass protrusions. The more light transmitted through the hole wall, the lower the backlight level, and the worse the hole wall metallization quality; conversely, the lower the level, the better. The difference in degreasing effect can be observed through the light transmitted through the hole wall (backlight levels range from 1 to 10; higher levels indicate better and more uniform copper plating. Conventional PCB mass production requires a backlight level of at least 9.0). The test results are shown in Tables 2 and 3 below.

[0083] Table 2: Results of Hole Wall Roughness Test

[0084]

[0085] As shown in Table 2, the backlight levels of the degreasing solutions 1-8 prepared in Examples 1-8 are all above level 9, indicating that the degreasing solution of the present invention can effectively adjust holes with large hole wall roughness and ensure good charge adjustment at each position of the hole wall. When performing chemical copper plating, it can uniformly plate a copper layer. In particular, when the hole wall roughness is between 25-30 μm and 30-35 μm, its backlight level is 1-1.5 levels higher than that of the degreasing solution of Comparative Example 1. The backlight level of the degreasing solution of Comparative Example 1 begins to decrease after the hole wall roughness is greater than 10 μm, and it is difficult to obtain a good chemical plating effect when the roughness is greater than 25 μm. However, the degreasing solution of the present invention still has a good chemical plating effect when the roughness is greater than 25 μm, indicating that the degreasing solution of the present invention can uniformly cover the chemical copper layer and meet the requirements of PCB mass production.

[0086] Table 3. Test results of fiberglass protrusion on the pore wall

[0087]

[0088] As shown in Table 3, the degreasing solutions 1-8 prepared in Examples 1-8 can effectively adjust the holes with severe glass fiber protrusions, ensuring good charge adjustment at the protruding glass fiber positions. During chemical copper plating, a copper layer can be uniformly plated. Moreover, when the glass fiber protrusions are between 20-25 μm and 25-30 μm, the backlight level is 1-1.5 levels higher than that of the degreasing solution in Comparative Example 1. The backlight level of the degreasing solution in Comparative Example 1 decreases after the glass fiber protrusions exceed 5 μm, and it is difficult to obtain a good chemical plating effect when the roughness is greater than 20 μm. However, the degreasing solution of the present invention still has a good chemical plating effect when the roughness is greater than 20 μm, indicating that the degreasing solution of the present invention can uniformly cover the chemical copper layer.

[0089] In summary, this invention provides a degreasing solution that can be used on non-conductive substrates of printed circuit boards and achieve uniform chemical copper plating. It is composed of ethanolamine, diethanolamine, a mixed quaternary ammonium salt, nonylphenol polyoxyethylene ether, and polyethylene glycol 1000, wherein the mixed quaternary ammonium salt is formulated from compound one and compound two. Compared with existing degreasing solutions, the degreasing solution of this invention has better charge adjustment and hole-forming capabilities, resulting in uniform charge distribution and thus a uniform copper plating layer thickness on the hole walls. This degreasing solution can adjust the charge on non-conductive substrates with normal roughness, as well as on non-conductive substrates with excessive hole wall roughness or fiberglass protrusion caused by poor drilling. This effectively reduces costs and defect rates. Furthermore, the method for preparing the degreasing solution is simple, highly operable, and suitable for industrial mass production.

[0090] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A degreasing solution for uniformly electroless copper plating on non-conductive substrates of printed circuit boards, characterized in that, The degreasing solution comprises 1–4 g / L ethanolamine, 4–7 g / L diethanolamine, 5–15 g / L mixed quaternary ammonium salt, 2–7 g / L nonylphenol polyoxyethylene ether, and 0.5–3 g / L polyethylene glycol 1000; wherein the mixed quaternary ammonium salt comprises compound one with the structural formula shown in formula (I) and compound two with the structural formula shown in formula (II); compound one and compound two are mixed in a mass ratio of 1–9:

1. (I) In formula (I), n = 1 to 7; (II)。 2. The degreasing solution for uniform chemical copper plating on non-conductive substrates of printed circuit boards according to claim 1, characterized in that, The degreasing solution comprises 1.5–3.5 g / L ethanolamine, 4.5–6.5 g / L diethanolamine, 5–15 g / L mixed quaternary ammonium salts, 4–5 g / L nonylphenol polyoxyethylene ether, and 1–2 g / L polyethylene glycol 1000.

3. The degreasing solution for uniform chemical copper plating on non-conductive substrates of printed circuit boards according to claim 1, characterized in that, The degreasing solution comprises 2.5 g / L ethanolamine, 5 g / L diethanolamine, 5 g / L mixed quaternary ammonium salt, 4.5 g / L nonylphenol polyoxyethylene ether, and 1.5 g / L polyethylene glycol 1000.

4. The degreasing solution for uniform chemical copper plating on non-conductive substrates of printed circuit boards according to claim 1, characterized in that, The mass ratio of compound one to compound two is (1-20):

1.

5. The degreasing solution for uniform chemical copper plating on non-conductive substrates of printed circuit boards according to claim 1, characterized in that, The mass ratio of compound one to compound two is 1:

1.

6. The method for preparing the degreasing solution for uniform chemical copper plating on a non-conductive substrate of a printed circuit board as described in any one of claims 1 to 5, characterized in that, The preparation method includes the following steps: S1. Under the catalysis of an alkali, triethanolamine and anhydrous ethanol are mixed and heated to 65°C-80°C, then raw material A is added and reacted for 4-6 hours, followed by separation and purification to obtain compound one; S2. Under the catalysis of an alkali, triethanolamine and anhydrous ethanol are mixed and heated to 65°C-80°C, then raw material B is added and reacted for 4-6 hours, followed by separation and purification to obtain compound two; S3. Compound one and compound two are mixed to prepare a mixed quaternary ammonium salt; S4. Ethanolamine, diethanolamine, nonylphenol polyoxyethylene ether, polyethylene glycol 1000, and the mixed quaternary ammonium salt are added to deionized water and mixed to prepare an oil removal solution; the raw material A is a dihaloalkyl ether, and its structural formula is shown in formula (III) below: (III) In formula (III), n = 1 to 7; X is a halogen atom; the raw material B is 1,4-dichlorobenzyl.

7. The method for preparing the degreasing solution for uniform chemical copper plating on a non-conductive substrate of a printed circuit board according to claim 6, characterized in that, In step S1, raw material A is added in 10 batches, with each batch spaced 2 hours apart.

8. The application of the degreasing solution for uniform electroless copper plating of non-conductive substrates of printed circuit boards as described in any one of claims 1 to 5, or the degreasing solution prepared by the preparation method described in any one of claims 6 to 7, in the degreasing process of electroless copper plating of printed circuit boards.

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