Chemical copper plating additive, chemical copper plating solution and IC carrier plate chemical copper plating method

Abstract

The invention discloses a chemical copper plating additive, a chemical copper plating solution and an IC carrier plate chemical copper plating method, and relates to the technical field of IC carrier plate production and manufacturing. The chemical copper plating additive is prepared from the following components in percentage by mass: 0.5 to 3.0 percent of complexing agent, 0.5 to 3.0 percent of reducing agent, 0.2 to 2.0 percent of accelerating agent, 0.5 to 3.0 percent of stabilizing agent, 0.2 to 2.0 percent of wetting agent and the balance of water. The chemical copper plating additive can effectively improve the stability of a chemical copper plating solution, the uniformity, the adhesive force and the deposition rate of a plating layer are good, and the deposition rate and the overflow plating degree can meet the production of IC carrier plate chemical copper plating.

Description

Technical Field

[0001] The invention relates to the technical field of IC carrier board production and manufacturing, and in particular to a chemical copper plating additive, a chemical copper plating solution and an IC carrier board chemical copper plating method. Background Art

[0002] IC substrate products are different from traditional printed circuit boards (PCBs). High processing difficulty and high investment threshold are the two core barriers of packaging substrates. From the perspective of product layers, board thickness, line width and line spacing, minimum ring width and other dimensions, IC substrates tend to be more precise and miniaturized. They are a more high-end PCB that can play a key role in supporting, connecting, dissipating heat and protecting chips.

[0003] There are many technical difficulties in the production process of IC substrates, which are mainly reflected in four aspects: pattern formation, copper plating, solder mask process and surface treatment. Among them, chemical copper plating is one of the important processes for metallization of non-metallic materials, especially in the field of PCB and substrates. The chemical copper layer is used as a conductive seed layer to facilitate the thickening of the metal layer in subsequent processes. Chemical plating is different from electroplating. Chemical copper plating does not require metal deposition under an external current. The reaction process will not have the problem of uneven distribution of electric lines on the surface of the plated part. The electroplating solution of chemical copper plating has a very strong dispersion ability. It can deposit a uniformly structured coating on parts with complex structures and uneven plated surfaces. Therefore, chemical copper plating is widely used in different fields.

[0004] The process flow of chemical copper plating is generally: expansion → degumming → pre-neutralization → neutralization → degreasing → micro-etching → pre-immersion → activation → reduction → chemical copper plating. Chemical copper plating is essentially an oxidation-reduction reaction of copper ions on the surface of a non-metallic substrate, and the reaction usually requires a catalyst to proceed. Under the action of a catalyst and a reducing agent on the surface of the substrate, the copper complex dissociates, and the copper ions gain electrons and are reduced to copper atoms, forming a metallic copper crystal layer on the surface. The chemical copper plating system using formaldehyde as a reducing agent is currently the most widely used, but there are also other systems using sodium hypophosphite as a reducing agent.

[0005] At present, there are some technical solutions related to chemical copper plating, such as patent CN 102277567 A discloses a chemical copper plating solution for micropore filling, the ingredients of which include copper sulfate pentahydrate, ethylenediaminetetraacetic acid, formaldehyde or glyoxylic acid, thiol-containing heterocyclic compounds, polyether with an average molecular weight of 3650, sodium hydroxide and an appropriate amount of distilled water, which realizes chemical copper plating filling of micropores without voids and gaps. Patent CN 105200402 A provides a chemical copper plating solution, which contains copper salt, reducing agent, complexing agent, pH regulator, optional stabilizer and optional surfactant, wherein the chemical copper plating solution contains 2-mercaptobenzothiazole and R1-SH, wherein R1 is a C8-C14 alkyl, which can effectively alleviate the overflow phenomenon, and the chemical copper plating solution used for chemical copper plating has a high plating speed and adhesion. Patent CN 112111731 A introduces a chemical copper plating solution and its preparation method and application. It can form a metal copper grid with a line width of 3-5μm by chemical deposition. The formed metal copper grid has a dense structure, a flat copper surface, no cracks or broken wires, no copper powder between the grid and the line, and good bonding between the copper film and the substrate without falling off. Patent CN 115261831 A also discloses a method for preparing an economical and environmentally friendly chemical copper plating solution, which is used to solve the problem that the existing chemical plating solution contains formaldehyde, has a low deposition rate, and is not stable.

[0006] The existing chemical copper plating technology has made great research progress in solving the problem of gaps in micropore filling and realizing environmental protection of plating solution. However, with the development of thin and lightweight substrates and localization, there is a huge demand for substrate production in the domestic market. Since the process size precision, quality, specifications and other requirements of the substrate are very strict, the chemical copper plating interconnection process will become more demanding in such a small space. The additives used in the plating solution will change in diffusion and adsorption behavior in such a confined space, which will inevitably be unfavorable for obtaining a densely grown copper layer in such a confined space. The existing technical solutions still have many defects in the production of substrates. Therefore, in order to adapt to the development of integrated circuits, it is urgent to develop a chemical copper plating additive suitable for IC substrates to reduce the defect rate of the production process and meet the production needs of substrates in chemical copper plating. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a chemical copper plating additive suitable for IC substrates and a preparation method and application thereof, which are specifically implemented through the following technical solutions.

[0008] Provided is an electroless copper plating additive, comprising the following components in mass fractions: Complexing agent 0.5-3.0%, Reducing agent 0.5-3.0%, Accelerator 0.2-2.0%, Stabilizer 0.5-3.0%, Wetting agent 0.2-2.0%, The balance is water; The complexing agent structural formula is as follows: ;

[0009] Where n is 4 or 6 or 8.

[0010] Preferably, the reducing agent is selected from at least one of 3,5-dichlorosalicylaldehyde (CAS No.: 90-60-8), 4,6-dichlorosalicylaldehyde (CAS No.: 78443-72-8), and 4,5-dichlorosalicylaldehyde (CAS No.: 84388-68-1).

[0011] Preferably, the accelerator is selected from at least one of cyclopropylphenyl sulfide (CAS No.: 14633-54-6), cyclobutylphenyl sulfide (CAS No.: 67132-84-7), and 2-nitrodiphenyl sulfide (CAS No.: 4171-83-9).

[0012] Preferably, the stabilizer is selected from at least one of 3-mercapto-N-methyl-propionamide (CAS No.: 52334-99-3), 3-mercapto-N-nonylpropionamide (CAS No. 228716-16-3), and 6-mercaptopyridine-3-sulfonamide (CAS No.: 10298-20-1).

[0013] Preferably, the wetting agent is selected from at least one of 3,5-dihydroxybenzohydrazide (CAS No.: 7732-32-3), 3,4-diaminobenzohydrazide (CAS No.: 103956-09-8), and 3-amino-4-hydroxybenzohydrazide (CAS No.: 7450-57-9).

[0014] Preferably, the preparation method of the complexing agent is as follows: Based on 100 parts by weight, 4-6 parts of catechol (CAS No.: 128-80-9), 0.8-1.2 parts of potassium carbonate (CAS No.: 584-08-7), 0.4-0.6 parts of potassium iodide (CAS No.: 7681-11-0), 4-6 parts of 2-chloroethoxyethanol (CAS No.: 628-89-7) and 25-35 parts of acetonitrile (CAS No.: 75-05-8) are added into a reaction container, and heated at 65-70°C for 1-2 hours; Then add 4-6 parts of 4-dimethylaminopyridine (abbreviated as DMAP; CAS number: 1122-58-3), 0.8-1.2 parts of triethylamine (abbreviated as Et3N; CAS number: 121-44-8), 1.5-2.5 parts of 1,2-dichloroethylene (CAS number: 540-59-0), 0.8-1.2 parts of p-toluenesulfonyl chloride (abbreviated as TsCl; CAS number: 98-59-9), and heat at 75-80°C for 3-4 hours; 0.4-0.6 parts of ethanol (CAS No.: 628-89-7) and 0.8-1.2 parts of toluene (CAS No.: 108-88-3) are added as solvents, and then 4-6 parts of alkane dithiol and the balance of water are added, and the mixture is heated at 85-90°C for 5-6 hours and then cooled to room temperature, and extracted with dichloromethane (CAS No.: 75-09-2) and water to obtain a complexing agent.

[0015] The alkane dithiol is selected from 1,4-butanedithiol (CAS No.: 1191-08-8), 1,6-hexanedithiol (CAS No.: 1191-43-1) or 1,8-octanedithiol (CAS No.: 1191-62-4).

[0016] In some specific embodiments, the preparation method of the complexing agent is as follows: Based on 100 parts by weight, 5 parts of catechol, 1 part of potassium carbonate, 0.5 parts of potassium iodide, 5 parts of 2-chloroethoxyethanol and 30 parts of acetonitrile were added to a reaction container and heated at 65° C. for 1 hour; Then add 5 parts of 4-dimethylaminopyridine, 1 part of triethylamine, 2 parts of 1,2-dichloroethylene, and 1 part of p-toluenesulfonyl chloride, and heat at 75°C for 3 hours; 0.5 parts of ethanol and 1 part of toluene were added as solvents, and then 5 parts of alkane dithiol and the balance 43 parts of water were added, and the mixture was heated at 85° C. for 5 hours and then cooled to room temperature. The complexing agent was extracted with dichloromethane and water.

[0017] In the chemical copper plating additive of the present invention, the complexing agent can react with copper ions to form a complex, which can not only improve the stability of the chemical copper plating solution and prevent secondary hydrolysis from generating copper hydroxide, but also improve the quality of the plated copper crystals, and at the same time have the effect of accelerating the chemical copper plating and improving the deposition rate of the copper plating; the reducing agent is used to reduce the copper ions in the complex to metallic copper. The reducing agent used in most of the existing PCB production is basically formaldehyde, which is extremely harmful to the human body. The present invention uses salicylaldehyde derivatives as reducing agents, which greatly reduces the harm caused by formaldehyde; the accelerator can effectively control the deposition rate in the chemical copper plating process and accelerate the chemical copper plating rate; the stabilizer can prevent the generation of small-particle copper crystals in the chemical copper plating process and improve the uniformity of the chemical copper plating. At the same time, the stabilizer can also improve the stability of the chemical copper plating solution and the life of the plating solution; the wetting agent can inhibit the generation of hydrogen in the chemical copper plating process to cause bubbles to appear on the surface of the plated copper film, thereby avoiding the occurrence of hydrogen embrittlement.

[0018] The invention also provides a chemical copper plating solution containing the chemical copper plating additive.

[0019] Preferably, the chemical copper plating solution is composed of the following components in mass fractions: 4-6% copper sulfate, 4-6% chemical copper plating additive, and the balance is water.

[0020] The present invention also provides an IC carrier chemical copper plating method, comprising a chemical copper plating step: immersing the IC carrier in the chemical copper plating solution at 50±0.2° C. for 35-45 minutes.

[0021] Preferably, the chemical copper plating process also includes an activation process before the process; the activation process specifically comprises: immersing the IC substrate in an activation tank solution at 25±5°C for 3±1 min; the activation tank solution contains 3% by mass hydrochloric acid and 5% by mass palladium chloride, with the remainder being DI water.

[0022] The chemical copper plating additive of the present invention contains five effective components, namely a reducing agent, an accelerator, a stabilizer, a wetting agent and a complexing agent, and can effectively improve the stability of the chemical copper plating solution. The uniformity, adhesion and deposition rate of the plating layer are good. The deposition rate and overflow plating degree can meet the production of chemical copper plating of IC carrier boards. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0024] Figure 1is the reaction formula for preparing the complexing agent in the embodiment of the present invention; Figure 2 This is a slicing effect diagram of an IC carrier board after chemical copper plating in Example 1 of the present invention; Figure 3 This is a diagram showing the effect of slicing an IC carrier board after chemical copper plating in comparative example 11 of the present invention. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The reaction formula for preparing the complexing agent in the following examples is as follows: Figure 1 As shown, the specific preparation method is as follows: according to 100 parts by weight of the total raw materials added to the three-necked flask, 5 parts of catechol, 1 part of potassium carbonate, 0.5 parts of potassium iodide, 5 parts of 2-chloroethoxyethanol and 30 parts of acetonitrile are added to the three-necked flask, and heated at 65°C for 1 hour; then 5 parts of 4-dimethylaminopyridine, 1 part of triethylamine, 2 parts of 1,2-dichloroethylene and 1 part of p-toluenesulfonyl chloride are added, and heated at 75°C for 3 hours; 0.5 parts of ethanol and 1 part of toluene are added as solvents, and then 5 parts of alkane dithiol (wherein the carbon number n of the alkane can be 4, 6, 8) and the balance 43 parts of water are added, and the mixture is heated at 85°C for 5 hours, then cooled to room temperature, and extracted with dichloromethane and distilled water for multiple times to obtain a complexing agent.

[0027] Example 1 According to the following mass concentration formula, the reducing agent, accelerator, stabilizer, wetting agent, complexing agent and distilled water are weighed in sequence and added into the reaction kettle. The chemical copper plating additive of this embodiment is obtained by stirring and mixing at room temperature for 30 minutes, and then sealed and stored for later use.

[0028] The reducing agent concentration is 1.5%, specifically 3,5-dichlorosalicylaldehyde; The accelerator concentration is 1.0%, specifically cyclopropylphenyl sulfide; The stabilizer concentration is 1.5%, specifically 3-mercapto-N-methyl-propionamide; The wetting agent concentration is 1.0%, specifically 3,5-dihydroxybenzohydrazide; The concentration of the complexing agent is 1.5%, and its structural formula is: ; The balance is distilled water.

[0029] Example 2 According to the following mass concentration formula, the reducing agent, accelerator, stabilizer, wetting agent, complexing agent and distilled water are weighed in sequence and added into the reaction kettle. The chemical copper plating additive of this embodiment is obtained by stirring and mixing at room temperature for 30 minutes, and then sealed and stored for later use.

[0030] The reducing agent concentration is 1.5%, specifically 4,6-dichlorosalicylaldehyde; The accelerator concentration is 1.0%, specifically cyclobutylphenyl sulfide; The stabilizer concentration is 1.5%, specifically 3-mercapto-N-nonylpropionamide; The wetting agent concentration is 1.0%, specifically 3,4-diaminobenzohydrazide; The concentration of the complexing agent is 1.5%, and its structural formula is: ; The balance is distilled water.

[0031] Example 3 According to the following mass concentration formula, the reducing agent, accelerator, stabilizer, wetting agent, complexing agent and distilled water are weighed in sequence and added into the reaction kettle. The chemical copper plating additive of this embodiment is obtained by stirring and mixing at room temperature for 30 minutes, and then sealed and stored for later use.

[0032] The reducing agent concentration is 1.5%, specifically 4,5-dichlorosalicylaldehyde; The accelerator concentration is 1.0%, specifically 2-nitrodiphenyl sulfide; The stabilizer concentration is 1.5%, specifically 6-mercaptopyridine-3-sulfonamide; The wetting agent concentration is 1.0%, specifically 3-amino-4-hydroxybenzoyl hydrazide; The concentration of the complexing agent is 1.5%, and its structural formula is: ; The balance is distilled water.

[0033] Example 4 According to the following mass concentration formula, the reducing agent, accelerator, stabilizer, wetting agent, complexing agent and distilled water are weighed in sequence and added into the reaction kettle. The chemical copper plating additive of this embodiment is obtained by stirring and mixing at room temperature for 30 minutes, and then sealed and stored for later use.

[0034] The reducing agent concentration is 0.5%, specifically 3,5-dichlorosalicylaldehyde; The concentration of the accelerator is 0.2%, specifically cyclopropylphenyl sulfide; The stabilizer concentration is 0.5%, specifically 3-mercapto-N-methyl-propionamide; The wetting agent concentration is 0.2%, specifically 3,5-dihydroxybenzohydrazide; The concentration of the complexing agent is 0.5%, and its structural formula is: ; The balance is distilled water.

[0035] Example 5 According to the following mass concentration formula, the reducing agent, accelerator, stabilizer, wetting agent, complexing agent and distilled water are weighed in sequence and added into the reaction kettle. The chemical copper plating additive of this embodiment is obtained by stirring and mixing at room temperature for 30 minutes, and then sealed and stored for later use.

[0036] The reducing agent concentration is 3.0%, specifically 3,5-dichlorosalicylaldehyde; The concentration of the accelerator is 2.0%, specifically cyclopropylphenyl sulfide; The stabilizer concentration is 3.0%, specifically 3-mercapto-N-methyl-propionamide; The wetting agent concentration is 2.0%, specifically 3,5-dihydroxybenzohydrazide; The concentration of the complexing agent is 3.0%, and its structural formula is: ; The balance is distilled water.

[0037] In the process of exploring the copper plating effects of chemical copper plating additives with different formulations, the present invention also prepared the following chemical copper plating additives of comparative examples.

[0038] Comparative Example 1 The chemical copper plating additive of Comparative Example 1 is different from that of Example 1 only in that the component does not contain a reducing agent.

[0039] Comparative Example 2 The chemical copper plating additive of Comparative Example 2 is different from that of Example 1 only in that the component does not contain an accelerator.

[0040] Comparative Example 3 The chemical copper plating additive of Comparative Example 3 is different from that of Example 1 only in that the component does not contain a stabilizer.

[0041] Comparative Example 4 The chemical copper plating additive of Comparative Example 4 is different from that of Example 1 only in that the component does not contain a wetting agent.

[0042] Comparative Example 5 The chemical copper plating additive of Comparative Example 5 is different from that of Example 1 only in that the component does not contain a complexing agent.

[0043] Comparative Example 6 The chemical copper plating additive of Comparative Example 6 is different from that of Example 1 only in that the reducing agent concentration in the component is 0.2%.

[0044] Comparative Example 7 The chemical copper plating additive of Comparative Example 7 is different from that of Example 1 only in that the concentration of the accelerator in the component is 0.1%.

[0045] Comparative Example 8 The chemical copper plating additive of Comparative Example 8 is different from that of Example 1 only in that the concentration of the stabilizer in the component is 0.2%.

[0046] Comparative Example 9 The chemical copper plating additive of Comparative Example 9 is different from that of Example 1 only in that the concentration of the wetting agent in the component is 0.1%.

[0047] Comparative Example 10 The chemical copper plating additive of Comparative Example 10 is different from that of Example 1 only in that the concentration of the complexing agent in the component is 0.2%.

[0048] Comparative Example 11 The chemical copper plating additive of Comparative Example 11 is a chemical copper plating additive disclosed in the prior art (Chinese patent application CN 110499501 A), and the specific ingredients include: formaldehyde 3 g / L; potassium sodium tartrate 80 g / L; 1,10-phenanthroline 5 mg / L; cytosine 5 mg / L; water-soluble polyethylene glycol (molecular weight 1000) 50 mg / L, and the balance is distilled water.

[0049] The chemical copper plating additives of the above embodiments or comparative examples are used for chemical copper plating of IC substrates (test samples), and the chemical copper plating process is: S1 water washing → S2 degreasing → S3 water washing → S4 micro-etching → S5 water washing → S6 pre-dipping → S7 activation → S8 chemical copper plating → S9 water washing → S10 drying. The details are as follows.

[0050] The S1 washing process is to wash the IC substrate with DI water to clean the surface impurities. The process parameters of the washing process are: spraying method, washing tank length 2.0 m, tank liquid temperature 25±5℃; line speed 3.0±0.5 m / min, pressure 1.5±0.5 kg / cm 2 ; The S2 degreasing process is to immerse the IC substrate after the S1 water washing process in an alkaline solution for degreasing; the process parameters of the degreasing process are: immersion method is adopted, the degreasing tank solution contains 1% by mass of sodium hydroxide, and the balance is DI water; the alkaline solution immersion time is 3±1 min, and the alkaline solution temperature is 50±5°C; The S3 washing process is to wash the IC substrate after the S2 degreasing process with DI water to clean the surface impurities. The process parameters of the washing process are: spraying method, the washing tank length is 2.0 m, the tank temperature is 25±5℃; the line speed is 3.0±0.5 m / min, and the pressure is 1.5±0.5 kg / cm 2 ; The S4 micro-etching process is to use an etching solution to micro-etch the surface of the IC carrier board after the S3 water washing process to improve the adhesion of the copper surface. The process parameters of the micro-etching process are: a spraying method is adopted, the micro-etching tank solution contains the micro-etching solution BTH-2011R of Shenzhen Banming Technology Co., Ltd., with a content of 5wt%, and the balance is DI water; the micro-etching tank is 2.0 m long, the tank liquid temperature is 25±5℃; the line speed is 3.0±0.5 m / min, and the pressure is 1.5±0.5 kg / cm 2 ; The S5 washing process is to wash the IC substrate after the S4 micro-etching process with DI water to clean the surface impurities. The process parameters of the washing process are: spraying method, the washing tank length is 2.0 m, the tank temperature is 25±5℃; the line speed is 3.0±0.5 m / min, and the pressure is 1.5±0.5 kg / cm 2 ; The S6 pre-dip process is to treat the IC substrate after the S5 water washing process with a pre-dip solution. The process parameters of the pre-dip process are: using an immersion method, the pre-dip tank solution contains 3% hydrochloric acid by mass, and the balance is DI water; the immersion time is 3±1min, and the pre-dip tank solution temperature is 25±5°C; The S7 activation process is to treat the IC substrate that has undergone the S6 pre-impregnation process with an activation solution. The process parameters of the activation process are: immersion is adopted, the activation tank solution contains 3% hydrochloric acid and 5% palladium chloride by mass, and the balance is DI water; the immersion time is 3±1 min, and the activation tank solution temperature is 25±5°C; The S8 chemical copper plating process is to treat the IC substrate after the S7 activation process with a chemical copper plating solution, and the process parameters of the chemical copper plating process are: an immersion method is adopted, the chemical copper plating solution in the chemical copper plating tank contains 5% by mass of copper sulfate and 5% by mass of the chemical copper plating additive of the embodiment of the present invention or the comparative example, and the balance is DI water; the immersion time is 40.0 min, and the temperature of the chemical copper plating solution is 50±0.2°C; The S9 washing process is to wash the IC substrate after the S8 chemical copper plating process with DI water to clean the surface impurities. The process parameters of the washing process are: spraying method, the washing tank length is 2.0 m, the tank temperature is 25±5℃; the line speed is 3.0±0.5 m / min, and the pressure is 1.5±0.5 kg / cm 2 ; The S10 drying process is to dry the IC substrate after the S9 washing process, and the drying process parameters are: temperature 70±5° C., drying section length 2.0 m, and line speed 4.0±0.3 m / min.

[0051] The IC substrate (test sample) after the chemical copper plating treatment in the above embodiment or comparative example was subjected to the following performance tests, and the specific test items and methods are as follows.

[0052] Plating solution stability: Use a beaker to take the chemical copper plating solution in the chemical copper plating tank of each embodiment or comparative example, leave it for 48 hours and observe the copper deposition.

[0053] Uniformity: Use a roughness measuring instrument to test the roughness value Ra of the coating. The lower the Ra value, the more uniform the coating surface. At the same time, observe whether small particles of copper crystals appear in the copper layer after chemical copper plating.

[0054] Adhesion: Keep the IC substrate after chemical copper plating at 260℃ for 1h, take it out and cool it in cold water; repeat 10 times without any peeling of the coating, it is qualified.

[0055] Deposition rate: The weight gain method is used for testing. Specifically, an ABF (Ajinomoto laminated film) substrate with a size of 50 cm long × 50 cm wide × 2 cm thick is placed in a chemical copper plating tank for copper plating for 1 hour. The mass before and after chemical copper plating is weighed. The deposition rate (μm / h) = chemical copper plating weight gain (g) × 11.2 × 60 / total deposition area (dm 2 ) × chemical copper plating time (h).

[0056] Overflow degree: Take an ABS+PC (linear carbonate polyester) composite substrate board with the size of 50cm long × 50cm wide × 2cm thick, among which the material of the middle part of the ABS+PC substrate board is ABS (250mm long × 25mm wide), and the material of the surrounding is PC; after degreasing and etching the ABS+PC board, use ion palladium activation solution to activate the substrate, so that only the ABS area is activated, and in the chemical plating process, the copper plating layer can only be formed in the ABS area; after chemical copper plating for 1 hour, use a dimension measuring instrument to measure the size of the copper plating layer in the length and width directions, and take the ratio of the difference between this size and the initial size of the ABS area to 2 as the overflow degree, measure 10 random positions with equal spacing along the length and width directions, and take the average value of all measured values ​​as the standard for evaluating the overflow degree.

[0057] The IC substrate performance test results of the above Examples 1-5 and Comparative Examples 1-11 are shown in Table 1.

[0058] Table 1 Performance test results

[0059] It can be seen from the test results of Examples 1-5 in Table 1 that the chemical copper plating solution obtained by using the chemical copper plating additive of the present invention has good stability, and there is no copper accumulation phenomenon after being placed for 48 hours; the uniformity and adhesion of the coating obtained after chemical copper plating are good, the Ra value is between 0.22-0.25, and there is no small particle crystallization in the coating; at the same time, the plating solution has a faster deposition rate, the rate is about 13.5μm / h, and the overflow degree is only 1.5-1.7μm, and can be used for the chemical copper plating production process of IC substrates.

[0060] The difference between comparative examples 1-5 and embodiment 1 is that the chemical copper plating additives of the present invention lack a single component of a reducing agent, an accelerator, a stabilizer, a wetting agent, and a complexing agent. The test results show that the chemical copper plating effect of the IC carrier is related to the effect of each additive component. The lack of any component will affect the stability, uniformity, adhesion, deposition rate and overflow degree of chemical copper plating. The role of the reducing agent is to reduce the copper ions in the complex to metallic copper. When the reducing agent is missing from the component, the coating cannot be obtained; the accelerator, the stabilizer, the wetting agent, and the complexing agent play corresponding functions. The complexing agent used in the present invention is a macrocyclic compound composed of a methylene bridge chain phenol unit, and its structural formula has abundant hydrocarbon reaction sites, and the upper edge, the lower edge and the sulfur atom of the bridge chain have the possibility of functionalization, and can show excellent complexing performance with metal ions. At the same time, the complexing agent has the effect of accelerating chemical copper plating and improving the stability of the chemical copper plating solution. When the complexing agent component is missing, the chemical copper plating effect decreases more significantly.

[0061] The difference between Comparative Examples 6-10 and Example 1 is that the reducing agent, accelerator, stabilizer, wetting agent and complexing agent in the chemical copper plating additive of the present invention are respectively lower than the lower limit of mass concentration specified in the present invention. The test results show that the reduction of the mass concentration of each component will reduce the effect of chemical copper plating and cannot meet the requirements of chemical copper plating of IC substrates. Therefore, the concentration of each component must be controlled within the concentration range of the present invention.

[0062] Comparative Example 11 uses a chemical copper plating solution containing a prior art chemical copper plating additive for comparison. The test results show that the chemical copper plating solution using the chemical copper plating additive of the present invention has better chemical copper plating stability, uniformity, adhesion, deposition rate and overflow degree.

[0063] Example 1 The IC substrate slicing effect after chemical copper plating is as follows Figure 2 As shown; Comparative Example 11 IC substrate slicing effect after chemical copper plating is as shown Figure 3 shown.

[0064] It can be seen that the chemical copper plating additive containing effective ingredients such as a reducing agent, an accelerator, a stabilizer, a wetting agent, a complexing agent, etc. of the present invention can effectively improve the stability of the chemical copper plating solution, and the uniformity, adhesion, and deposition rate of the plating layer are good. The deposition rate and overflow plating degree can meet the production of chemical copper plating of IC substrates.

[0065] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. An additive for chemical copper plating, characterized in that: It is composed of the following components in mass fractions: Complexing agent 0.5-3.0%, Reducing agent 0.5-3.0%, Accelerator 0.2-2.0%, Stabilizer 0.5-3.0%, Wetting agent 0.2-2.0%, The balance is water; The complexing agent structural formula is as follows: ； Where n is 4 or 6 or 8.

2. The chemical copper plating additive according to claim 1, characterized in that: The reducing agent is selected from at least one of 3,5-dichlorosalicylaldehyde, 4,6-dichlorosalicylaldehyde and 4,5-dichlorosalicylaldehyde.

3. The chemical copper plating additive according to claim 1, characterized in that: The accelerator is selected from at least one of cyclopropylphenyl sulfide, cyclobutylphenyl sulfide and 2-nitrodiphenyl sulfide.

4. The chemical copper plating additive according to claim 1, characterized in that: The stabilizer is selected from at least one of 3-mercapto-N-methyl-propionamide, 3-mercapto-N-nonylpropionamide, and 6-mercaptopyridine-3-sulfonamide.

5. The chemical copper plating additive according to claim 1, characterized in that: The wetting agent is selected from at least one of 3,5-dihydroxybenzohydrazide, 3,4-diaminobenzohydrazide and 3-amino-4-hydroxybenzohydrazide.

6. The chemical copper plating additive according to claim 1, characterized in that: The preparation method of the complexing agent is as follows: Based on 100 parts by weight, 4-6 parts of catechol, 0.8-1.2 parts of potassium carbonate, 0.4-0.6 parts of potassium iodide, 4-6 parts of 2-chloroethoxyethanol and 25-35 parts of acetonitrile are added into a reaction container, and heated at 65-70° C. for 1-2 hours; Then add 4-6 parts of 4-dimethylaminopyridine, 0.8-1.2 parts of triethylamine, 1.5-2.5 parts of 1,2-dichloroethylene, and 0.8-1.2 parts of p-toluenesulfonyl chloride, and heat at 75-80° C. for 3-4 hours; Add 0.4-0.6 parts of ethanol and 0.8-1.2 parts of toluene as solvents, add 4-6 parts of alkane dithiol and the balance of water, heat at 85-90° C. for 5-6 hours, cool to room temperature, and extract with dichloromethane and water to obtain a complexing agent; The alkane dithiol is selected from 1,4-butanedithiol, 1,6-hexanedithiol or 1,8-octanedithiol.

7. A chemical copper plating solution, characterized in that Contains the chemical copper plating additive as described in any one of claims 1 to 6.

8. The chemical copper plating solution according to claim 7, characterized in that: The invention is composed of the following components in mass fractions: 4-6% copper sulfate, 4-6% chemical copper plating additive, and the balance being water.

9. A method for chemical copper plating of an IC substrate, characterized in that: The method comprises a chemical copper plating step of immersing the IC substrate in the chemical copper plating solution as claimed in claim 7 or 8 at 50±0.2° C. for 35-45 minutes.

10. The IC substrate chemical copper plating method according to claim 9, characterized in that: The chemical copper plating process also includes an activation process before the process; the activation process is specifically: immersing the IC substrate in an activation tank solution at 25±5°C for 3±1min; the activation tank solution contains 3% by mass hydrochloric acid and 5% by mass palladium chloride, and the remainder is DI water.

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