A nickel removing agent for IC carrier plate, a preparation method and a nickel removing method thereof

Abstract

The application discloses an IC carrier plate nickel removing agent and a preparation method and a nickel removing method thereof, and relates to the technical field of semiconductor packaging. The IC carrier plate nickel removing agent comprises the following mass concentration components: 3.0-8.0% of a main reaction agent, 1.0-5.0% of a complexing agent, 1.0-5.0% of a wetting agent, 1.0-5.0% of an accelerator and 0.5-2.5% of a stabilizer; the main reaction agent is one or more of benzene ethyl peroxo acid 1,1-dimethyl ethyl ester, methyl peroxo acid 1,1-dimethyl ethyl ester and perisopropyl acid-1,1-dimethyl ethyl ester; and the complexing agent is one or more of N,N-dimethyl imidazole-1-sulfonamide, N-cyclohexyl p-toluenesulfonamide and 2-acrylamido-2-methyl propane sulfonic acid. The application provides an IC carrier plate nickel removing agent and a preparation method and a nickel removing method thereof; the IC carrier plate nickel removing agent has the effects of efficient nickel removing performance and non-corrosion of copper at normal temperature.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging technology, and in particular to an IC substrate nickel stripping agent and its preparation and stripping methods. Background Technology

[0002] In the field of semiconductor packaging technology, IC substrates are the key carriers connecting semiconductor chips and printed circuit boards. The electrical performance and reliability of the chips are directly affected by the quality of the metal plating on the surface of the IC substrate. During the IC substrate production process, if the nickel plating has defects (such as pinholes, uneven plating, impurities, etc.), or if secondary adjustments to the substrate surface pattern are required, the deposited nickel layer must be removed to enable the recycling and reuse of the substrate or to create conditions for subsequent replating.

[0003] Currently, nickel stripping technology for IC substrates mainly relies on two types of solutions (nickel stripping agents): The first type is alkaline nickel stripping solutions containing cyanide. Although these solutions strip nickel quickly, cyanide itself is highly toxic, posing a serious threat to the personal safety of operators and generating toxic wastewater that is difficult to treat, failing to meet current environmental regulations. The second type is acidic nickel stripping solutions (commonly nitric acid-fluoride systems and sulfuric acid-chromic anhydride systems). While these solutions avoid the toxicity of cyanide, they have significant drawbacks. The nitric acid-fluoride system severely corrodes the copper substrate of the IC substrate, leading to a thinner substrate, deformation of the circuit pattern, and ultimately a decrease in the mechanical strength and electrical connection stability of the substrate. The sulfuric acid-chromic anhydride system contains hexavalent chromium, a heavy metal pollutant that easily accumulates in the environment. Furthermore, the residual chromium ions after nickel stripping can adversely affect the adhesion between subsequent plating layers and the substrate, causing problems such as secondary plating peeling and blistering. In addition, some existing nickel stripping solutions have other shortcomings: on the one hand, the nickel stripping speed is slow (usually less than 1 μm / min), and on the other hand, nickel ions are prone to precipitation. This phenomenon directly leads to a short service life of the solution (usually less than 8 hours). These problems together make it difficult for such solutions to meet the efficiency requirements of industrial mass production of IC substrates.

[0004] In addition, various nickel stripping solutions have been developed in existing technologies. For example, Chinese patent CN106757032A describes a method for preparing an organic acid nickel stripping agent, which avoids the harm of nitric acid to the human body and meets environmental protection requirements. Chinese patent CN 110629224B provides an environmentally friendly nickel stripping agent and its preparation and application methods. Its components consist of sulfuric acid, hydrogen peroxide, nitric acid, disodium ethylenediaminetetraacetate and other complexing agents, m-nitrobenzenesulfonic acid and other stabilizers, isopropanol and other accelerators. Its nickel plating layer removal rate reaches 2-4 μm / min, and it does not corrode stainless steel substrates. Chinese patent CN114959709B discloses an environmentally friendly nickel stripping agent that can solve the problem that concentrated nitric acid or other strong oxidizing agents in nickel stripping agents can easily damage the metal substrate or produce toxic and harmful gases such as sulfur dioxide or nitrogen oxides that pollute the atmosphere. Chinese patent CN115772670A introduces an industrial nickel stripping agent suitable for nickel-plated circuit boards and its application method. It consists of hydrofluoric acid, citric acid, hydrogen peroxide, benzotriazole, and a brightener, solving the technical problem of copper damage to the substrate during the stripping process. Current technology can solve the production problems of nickel stripping processes for printed circuit boards. However, facing the development of lightweight, high-density, high-frequency, and high-speed electronic products, there is a need to develop a nickel stripping agent suitable for IC substrates to meet the production process requirements of semiconductor packaging. The current bottlenecks in nickel stripping technology are specifically manifested in: the lack of stability in the nickel stripping rate, and the accumulation of nickel ions easily leading to chemical deactivation; the stripping effect is not ideal for high-phosphorus nickel commonly used in IC substrates; there is still a slight risk of corrosion to the copper substrate, which will affect the quality of subsequent re-nickel plating; and the need to maintain a relatively high temperature during operation, which not only results in high energy consumption but also easily causes chemical decomposition.

[0005] Therefore, developing an IC substrate nickel stripping agent that is fast, has low corrosion rate on copper substrates, is environmentally friendly and free of pollutants, and has high stability has become an urgent technical problem to be solved in the current semiconductor packaging field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an IC substrate nickel stripping agent and its preparation and stripping methods. This nickel stripping agent contains effective components such as a main reactant, a coordinating agent, a wetting agent, an accelerator, and a stabilizer. The nickel stripping agent of this invention exhibits a nickel stripping speed of 3.75-3.86 μm / min and a copper stripping speed ≤0.0025 μm / min, demonstrating excellent nickel stripping performance. Simultaneously, the peel strength of the secondary nickel plating layer after nickel stripping reaches 17.5-19.0 N / cm, and the exposed copper surface after complete nickel stripping is bright and smooth, meeting the requirements of the IC substrate nickel stripping process.

[0007] In a first aspect, an IC substrate nickel stripping agent is provided, comprising the following components by mass concentration: 3.0-8.0% main reactant, 1.0-5.0% ligand, 1.0-5.0% wetting agent, 1.0-5.0% accelerator, and 0.5-2.5% stabilizer;

[0008] The main reactant is one or more of the following: 1,1-dimethyl ethyl phenylperoxy acid (CAS No.: 3377-89-7), 1,1-dimethyl ethyl methylperoxy acid (CAS No.: 819-50-1), and 1,1-dimethyl ethyl perisononanoate (CAS No.: 27836-52-8);

[0009] The ligand is one or more of N,N-dimethylimidazolium-1-sulfonamide (CAS No.: 78162-58-0), N-cyclohexyl-p-toluenesulfonamide (CAS No.: 80-30-8), and 2-acrylamido-2-methylpropanesulfonic acid (CAS No.: 15214-89-8).

[0010] In this process, the main reactant and the ligand break the metallic bonds of nickel through a "coordination-assisted oxidation" mechanism. The main reactant provides sufficiently strong oxidizing power to strip electrons from nickel atoms (Ni), converting them into soluble nickel ions. ), breaking the electron-sharing structure of metallic bonds; ligands interact with functional groups Forming stable complexes, avoiding Redeposition ensures the oxidation reaction continues uninterrupted, preventing the breaking of metallic bonds. Wetting agents reduce the surface tension of the stripping agent, allowing it to spread and penetrate rapidly on the hydrophobic nickel metal surface, especially reaching microscopic defects and grain boundaries. Accelerators increase the rate at which Ni atoms lose electrons, preventing slow oxidation from slowing down the overall reaction, while also rapidly stabilizing the generated material. This prevents it from depositing on the nickel layer surface and hindering subsequent reaction contact. The stabilizer works by "fixing..." The solution is to "protect the oxidant and isolate the substrate". Problems such as precipitation, decomposition of the main reactant, and corrosion of the substrate are addressed to ensure the stability of the nickel stripping agent's performance.

[0011] Furthermore, the wetting agent is one or more of 1H,1H,2H,2H-perfluorooctyl mercaptan (CAS No.: 34451-26-8), 1H,1H,2H,2H-perfluorodecyl mercaptan (CAS No.: 34143-74-3), and 5-fluoro-2-mercaptobenzyl alcohol (CAS No.: 870703-84-7).

[0012] Furthermore, the accelerator is one or more of 2-amino-5-bromobenzoic acid (CAS No.: 5794-88-7), 4-amino-2,6-dimethylbenzoic acid (CAS No.: 16752-16-2), and 2-amino-3-methylbenzoic acid (CAS No.: 4389-45-1).

[0013] Furthermore, the stabilizer is one or more of 2-mercapto-5-fluorobenzimidazole (CAS No.: 583-42-6), 5-difluoromethoxy-2-mercapto-1H-benzimidazole (CAS No.: 97963-62-7), and 4-chloro-2-mercapto-6-(trifluoromethyl)benzimidazole (CAS No.: 175135-18-9).

[0014] Furthermore, the IC substrate nickel stripping agent comprises the following components by mass concentration: main reactant 3.0-6.0%, ligand 1.0-3.0%, wetting agent 1.0-3.0%, accelerator 1.0-3.0%, and stabilizer 0.5-1.5%.

[0015] Furthermore, the IC substrate nickel stripping agent is composed of the following components in mass concentrations: main reactant 3.0-6.0%, ligand 1.0-3.0%, wetting agent 1.0-3.0%, accelerator 1.0-3.0%, stabilizer 0.5-1.5%, and the balance being water.

[0016] Secondly, a method for preparing the nickel stripping agent for IC substrates according to the first aspect is provided, comprising the following steps: weighing the main reactant, ligand, wetting agent, accelerator, stabilizer and water in sequence and adding them to a reaction vessel, and stirring and mixing at room temperature of 25-28°C for 30-35 minutes to obtain the final product.

[0017] Thirdly, a method for removing nickel from an IC substrate using the nickel stripping agent described in the first aspect is provided, comprising the following steps: using the nickel stripping agent described in the first aspect to perform nickel stripping treatment on the IC substrate.

[0018] Furthermore, the nickel stripping process involves immersing the IC carrier in a pre-immersion tank using an IC carrier nickel stripping agent, followed by ultrasonic-assisted treatment under conditions of an ultrasonic frequency of 28-40kHz and a power of 100-150W.

[0019] Preferably, the nickel stripping agent for the IC substrate is present in a 20% (by mass) solution in the pre-immersion tank, with the remainder being tap water.

[0020] Furthermore, the nickel stripping process is performed at a temperature of 25±1℃ and a linear velocity of 3.0±0.2 m / min.

[0021] The beneficial effects of this invention are as follows:

[0022] 1. The nickel stripping agent for IC substrates at room temperature has excellent nickel stripping speed and low copper stripping speed, combining high-efficiency nickel stripping performance with the effect of not corroding copper.

[0023] 2. The peel strength of the secondary nickel plating layer after nickel stripping is high, which can meet the reliability requirements of IC substrates;

[0024] 3. The exposed copper surface after complete nickel stripping is bright and smooth, which is very beneficial for re-nickel plating after repair. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a 1000x SEM image of the copper surface after being treated with the nickel stripping method according to Example 1 of the present invention;

[0027] Figure 2 This is a 1000x SEM image of the copper surface after nickel stripping treatment using Comparative Example 16 of the present invention. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0029] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0030] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0031] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0032] To better understand the technical content of the present invention, the technical solution of the present invention will be further introduced and explained below with reference to specific embodiments.

[0033] Unless otherwise stated, "%" in this invention refers to mass concentration.

[0034] The nickel stripping method for the IC substrate nickel stripping agent includes the following steps:

[0035] S1 Degreasing; S2 Water washing; S3 Nickel stripping; S4 Water washing; S5 Passivation; S6 Water washing; S7 Drying.

[0036] The S1 degreasing process is used to remove surface impurities from IC substrates that require nickel stripping. The degreasing process parameters are as follows: a spray method is used; the degreasing tank consists of 5% sodium hydroxide (CAS No.: 1310-73-2) and the remainder is tap water; the tank length is 2.0 m, the tank temperature is 25±1 ℃, the linear velocity is 4.0±0.2 m / min, and the spray pressure is 1.0±0.1 kg / cm². 2 ;

[0037] The S2 water wash involves rinsing the IC carrier board, which has undergone oil removal in S1, with tap water. The process parameters for the water wash are as follows: spray method, water tank length 2.0 m, tank liquid temperature 25±1 ℃; linear velocity 3.0±0.2 m / min, pressure 1.0±0.1 kg / cm². 2 ;

[0038] The S3 nickel stripping process involves using the nickel stripping agent of this invention to strip the nickel from the IC substrate that has undergone the S2 water washing. The process employs an immersion + ultrasonic-assisted treatment method. The immersion treatment involves using the nickel stripping agent of this invention in a pre-immersion tank, with a solution concentration of 20% (by mass) and the remainder being tap water, to immerse the IC substrate. The ultrasonic-assisted treatment is performed at an ultrasonic frequency of 28-40kHz and a power of 100-150W. The pre-immersion tank temperature is 25±1℃, the tank length is 4.0 m, and the linear velocity is 2.0±0.1 m / min.

[0039] The S4 water wash involves rinsing the IC substrate that has undergone nickel stripping in S3 with tap water. The process parameters for the water wash are as follows: spray method, water tank length 2.0 m, tank temperature 25±1 ℃; linear velocity 3.0±0.2 m / min, pressure 1.0±0.1 kg / cm². 2 ;

[0040] The S5 passivation process involves protecting the exposed copper surface of the IC substrate after nickel stripping using a passivation solution following the S4 water washing. The passivation process parameters are as follows: a spray method is used; the passivation solution consists of 5% benzotriazole (CAS No.: 95-14-7) and the remainder is tap water; the passivation tank is 2.0 m long, the tank temperature is 25±1 ℃, the linear velocity is 4.0±0.2 m / min, and the spray pressure is 1.0±0.1 kg / cm². 2 ;

[0041] The S6 water wash involves rinsing the IC substrate that has undergone S5 passivation with tap water. The process parameters for the water wash are as follows: spray method, water tank length 2.0 m, tank liquid temperature 25±1 ℃, linear velocity 3.0±0.2 m / min, and pressure 1.0±0.1 kg / cm². 2 ;

[0042] The S7 drying process involves drying the IC substrate that has been washed in the S6 process. The drying parameters are: temperature 70±1 ℃, drying section length 2.0 m, and linear speed 2.0±0.1 m / min.

[0043] Performance testing:

[0044] The performance of the IC substrate nickel stripping agent of this invention is mainly reflected in three aspects:

[0045] The first test involves evaluating the nickel and copper stripping speeds of the IC substrate nickel stripping agent. The specific procedure is as follows: Cut the nickel-plated or copper-plated board into a rectangular plate with length L and width M, where the units for length and width are cm. Then, perform the test according to the nickel stripping method for the IC substrate nickel stripping agent. Record the weight before the test as W2 (in g) and the weight after the test as W1 (in g). Calculate the nickel or copper stripping rate V using the following formula, in μm / min.

[0046] ;

[0047] Where ρ is the density of the nickel-plated or copper-plated plate, in g / cm³. 3 ;

[0048] Requirements: The nickel stripping speed of this invention is 3.0-4.0 μm / min, and the copper stripping speed is <0.1 μm / min.

[0049] The second test is to test the peel strength of the secondary nickel plating layer after nickel stripping. The specific operation is as follows: the secondary nickel plating of the IC substrate after complete nickel stripping is tested using an HTS-LLY2600 tensile tester. The peel angle is set to 90 degrees and the tensile speed is 50 mm / min. The average force value (in N) is obtained. The width of the nickel plating layer of the IC substrate (in cm) is measured using a vernier caliper. Peel strength (in N / cm) = average force value ÷ nickel plating layer width.

[0050] Requirements: Peel strength = 15-20 N / cm, which meets the reliability requirements of IC substrates.

[0051] The third point is to observe the appearance of the copper surface after complete nickel stripping, which should be bright and smooth.

[0052] Example 1

[0053] An IC substrate nickel stripping agent, comprising the following components by mass concentration:

[0054] The main reactant was 4.0%, specifically 1,1-dimethyl ethyl phenylacetoperoxy acid;

[0055] The ligand is 2.0%, specifically N,N-dimethylimidazolium-1-sulfonamide;

[0056] The wetting agent is 1.5%, specifically 1H,1H,2H,2H-perfluorooctyl mercaptan;

[0057] Accelerator 1.5%, specifically 2-amino-5-bromobenzoic acid;

[0058] Stabilizer 1.0%, specifically 2-mercapto-5-fluorobenzimidazole;

[0059] The remainder is water.

[0060] The preparation method of the IC substrate nickel stripping agent includes the following steps: weighing the main reactant, ligand, wetting agent, accelerator, stabilizer and water in sequence and adding them to the reaction vessel, stirring and mixing at room temperature of 25°C for 30 minutes to obtain the final product.

[0061] The nickel stripping method for the IC substrate nickel stripping agent includes the following steps:

[0062] S1 Degreasing; S2 Water washing; S3 Nickel stripping; S4 Water washing; S5 Passivation; S6 Water washing; S7 Drying;

[0063] The S3 nickel stripping process involves using the nickel stripping agent of this invention to strip the nickel from the IC substrate that has undergone the S2 water washing. The process employs an immersion + ultrasonic-assisted treatment method. The immersion treatment involves using the nickel stripping agent of this invention in a pre-immersion tank, with a solution concentration of 20% (by mass) and the remainder being tap water, to immerse the IC substrate. The ultrasonic-assisted treatment is performed at an ultrasonic frequency of 35kHz and a power of 125W. The pre-immersion tank temperature is 25℃, the tank length is 4.0 m, and the linear velocity is 2.0 m / min.

[0064] The preparation methods of the nickel stripping agents for IC substrates in Examples 2-5 and Comparative Examples 1-16 were the same as those in Example 1. The nickel stripping methods of the nickel stripping agents for IC substrates in Examples 2-5 and Comparative Examples 1-16 were the same as those in Example 1.

[0065] Example 2

[0066] An IC substrate nickel stripping agent, comprising the following components by mass concentration:

[0067] The main reactant was 4.0%, specifically 1,1-dimethyl ethyl methylperoxy acid;

[0068] The ligand is 2.0%, specifically N-cyclohexyl-p-toluenesulfonamide;

[0069] The wetting agent is 1.5%, specifically 1H,1H,2H,2H-perfluorodecylthiol;

[0070] Accelerator 1.5%, specifically 4-amino-2,6-dimethylbenzoic acid;

[0071] Stabilizer 1.0%, specifically 5-difluoromethoxy-2-mercapto-1H-benzimidazole;

[0072] The remainder is water.

[0073] Example 3

[0074] An IC substrate nickel stripping agent, comprising the following components by mass concentration:

[0075] The main reactant was 4.0%, specifically 1,1-dimethyl ethyl perisononanoic acid;

[0076] The ligand is 2.0%, specifically 2-acrylamido-2-methylpropanesulfonic acid;

[0077] The wetting agent is 1.5%, specifically 5-fluoro-2-mercaptobenzyl alcohol;

[0078] Accelerator 1.5%, specifically 2-amino-3-methylbenzoic acid;

[0079] Stabilizer 1.0%, specifically 4-chloro-2-mercapto-6-(trifluoromethyl)benzimidazole;

[0080] The remainder is water.

[0081] Example 4

[0082] An IC substrate nickel stripping agent, comprising the following components by mass concentration:

[0083] The main reactant is 3.0%, specifically 1,1-dimethyl ethyl phenylacetoperoxy acid;

[0084] The ligand is 1.0%, specifically N,N-dimethylimidazolium-1-sulfonamide;

[0085] The wetting agent is 1.0%, specifically 1H,1H,2H,2H-perfluorooctyl mercaptan;

[0086] Accelerator 1.0%, specifically 2-amino-5-bromobenzoic acid;

[0087] Stabilizer 0.5%, specifically 2-mercapto-5-fluorobenzimidazole;

[0088] The remainder is water.

[0089] Example 5

[0090] An IC substrate nickel stripping agent, comprising the following components by mass concentration:

[0091] The main reactant is 6.0%, specifically 1,1-dimethyl ethyl phenylacetochlor;

[0092] The ligand is 3.0%, specifically N,N-dimethylimidazolium-1-sulfonamide;

[0093] The wetting agent is 3.0%, specifically 1H,1H,2H,2H-perfluorooctyl mercaptan;

[0094] Accelerator 3.0%, specifically 2-amino-5-bromobenzoic acid;

[0095] Stabilizer 1.5%, specifically 2-mercapto-5-fluorobenzimidazole;

[0096] The remainder is water.

[0097] Comparative Example 1

[0098] Comparative Example 1 provides a nickel stripping agent for IC substrates. The only difference between Comparative Example 1 and Example 1 is that the components do not contain the main reactant.

[0099] Comparative Example 2

[0100] Comparative Example 2 provides a nickel stripping agent for IC substrates. The only difference between Comparative Example 2 and Example 1 is that the components do not contain a coordinating agent.

[0101] Comparative Example 3

[0102] Comparative Example 3 provides a nickel stripping agent for IC substrates. The only difference between Comparative Example 3 and Example 1 is that the components do not contain a wetting agent.

[0103] Comparative Example 4

[0104] Comparative Example 4 provides a nickel stripping agent for IC substrates. The only difference between Comparative Example 4 and Example 1 is that the components do not contain an accelerator.

[0105] Comparative Example 5

[0106] Comparative Example 5 provides a nickel stripping agent for IC substrates. The only difference between Comparative Example 5 and Example 1 is that the components do not contain stabilizers.

[0107] Comparative Example 6

[0108] Comparative Example 6 provides a nickel stripping agent for IC substrates. The only difference between Comparative Example 6 and Example 1 is that the mass concentration of the main reactant in the component is 10.0%.

[0109] Comparative Example 7

[0110] Comparative Example 7 provides a nickel stripping agent for IC substrates. The only difference between Comparative Example 7 and Example 1 is that the mass concentration of the ligand in the component is 6.0%.

[0111] Comparative Example 8

[0112] Comparative Example 8 provides a nickel stripping agent for IC substrates. The only difference between Comparative Example 8 and Example 1 is that the mass concentration of the wetting agent in the component is 6.0%.

[0113] Comparative Example 9

[0114] Comparative Example 9 provides a nickel stripping agent for IC substrates. The only difference between Comparative Example 9 and Example 1 is that the mass concentration of the accelerator in the component is 6.0%.

[0115] Comparative Example 10

[0116] Comparative Example 10 provides a nickel stripping agent for IC substrates. The only difference between Comparative Example 10 and Example 1 is that the mass concentration of the stabilizer in the component is 3.0%.

[0117] Comparative Example 11

[0118] Comparative Example 11 provides a nickel stripping agent for IC substrates. The only difference between Comparative Example 11 and Example 1 is that the main reactant is replaced with ammonium persulfate (CAS No.: 7727-54-0) of the same mass concentration.

[0119] Comparative Example 12

[0120] Comparative Example 12 provides an IC substrate nickel stripping agent. The only difference between Comparative Example 12 and Example 1 is that the ligand is replaced with an equal mass concentration of methanesulfonamide (CAS No.: 3144-09-0).

[0121] Comparative Example 13

[0122] Comparative Example 13 provides a nickel stripping agent for IC substrates. The only difference between Comparative Example 13 and Example 1 is that the wetting agent is replaced with an equal mass concentration of ethanethiol (CAS No.: 75-08-1).

[0123] Comparative Example 14

[0124] Comparative Example 14 provides a nickel stripping agent for IC substrates. The only difference between Comparative Example 14 and Example 1 is that the accelerator is replaced with benzoic acid (CAS No.: 65-85-0) of the same mass concentration.

[0125] Comparative Example 15

[0126] Comparative Example 15 provides a nickel stripping agent for IC substrates. The only difference between Comparative Example 15 and Example 1 is that the stabilizer is replaced with benzimidazole (CAS No.: 51-17-2) of the same mass concentration.

[0127] Comparative Example 16

[0128] Comparative Example 16 provides an IC substrate nickel stripping agent, which is a nickel stripping solution using prior art (Chinese Patent CN110629224B), composed of the following components by mass concentration: sulfuric acid 3.0%; hydrogen peroxide 2.0%; nitric acid 0.4%; sodium p-hydroxybenzenesulfonate 0.1%; disodium ethylenediaminetetraacetate 0.1%; ethylene glycol 0.1%; and the balance being water.

[0129] The IC substrates treated with the nickel stripping agents of Examples 1-5 were subjected to performance tests, and the test results are shown in Table 1.

[0130] Table 1. Performance test results of nickel stripping agent for IC substrates in Examples 1-5

[0131]

[0132] The IC substrates of Comparative Examples 1-16 were subjected to performance tests after being treated with the nickel stripping agent by the nickel stripping method. The test results are shown in Table 2.

[0133] Table 2. Test results of nickel stripping agent performance of IC substrates in Comparative Examples 1-16

[0134]

[0135] Figure 1 This is a 1000x SEM image of the copper surface after being treated with the nickel stripping method according to Example 1 of the present invention; Figure 2 This is a 1000x SEM image of the copper surface after nickel stripping treatment using Comparative Example 16 of the present invention.

[0136] As shown in Table 1, the nickel stripping speed of the IC substrate stripping agent in this embodiment is 3.75-3.86 μm / min, and the copper stripping speed is ≤0.0025 μm / min, demonstrating good nickel stripping performance and non-corrosive effect on copper. At the same time, the peel strength of the secondary nickel plating layer after nickel stripping reaches 17.5-19.0 N / cm, and the exposed copper surface after complete nickel stripping is bright and smooth, which can meet the requirements of the IC substrate nickel stripping process.

[0137] As shown in Table 2, the difference between Comparative Examples 1-5 and Example 1 lies in the absence of five individual components in the present invention's IC substrate nickel stripping agent: the main reactant, the coordinating agent, the wetting agent, the accelerator, and the stabilizer. The experimental data reveals that the main reactant and the coordinating agent are crucial for achieving the nickel stripping effect: they break the metallic bonds of nickel through a "coordination-assisted oxidation" process, thereby removing the nickel from the IC substrate. The absence of either one significantly reduces the nickel stripping speed and increases the copper stripping rate, leading to uneven copper surfaces and reduced peel strength. The wetting agent, accelerator, and stabilizer primarily play auxiliary roles, including accelerating the nickel stripping speed, reducing the surface tension of the IC substrate nickel stripping agent, protecting the copper surface and the substrate surface, and improving the stability of the nickel stripping agent system. The absence of any one of these three components also leads to a decrease in the performance of the IC substrate nickel stripping agent. This result demonstrates that the excellent performance of the present invention's IC substrate nickel stripping agent stems from the synergistic effect of its components.

[0138] The main difference between Comparative Examples 6-10 and Example 1 is that the mass concentrations of the five individual components—main reactant, ligand, wetting agent, accelerator, and stabilizer—in the IC substrate nickel stripping agent in Comparative Examples 6-10 exceed the upper limits of the mass concentrations specified in this invention. Experimental data show that, compared with Examples 1-5, excessively high mass concentrations of these components do not affect the performance of the IC substrate nickel stripping agent, but significantly increase the preparation cost. Therefore, the IC substrate nickel stripping agent of this invention does not require excessively high mass concentrations for each component; as long as the concentrations are controlled within the range described in the examples, good nickel stripping performance of the IC substrate nickel stripping agent can be ensured.

[0139] The difference between Comparative Examples 11-15 and Example 1 is that the former replaces the main reactant, ligand, wetting agent, accelerator, and stabilizer with other compounds of equal mass concentration and with similar structures or functions. Experimental data show that using corresponding functional components with different branched structures or functional group types significantly affects the nickel stripping performance, making it difficult to achieve the effect required by this invention.

[0140] The difference between Comparative Example 16 and Example 1 is that a nickel stripping solution with existing patents is used for comparison. Experimental data shows that the nickel stripping agent of the present invention for IC substrates has significant advantages: better nickel stripping speed, minimal corrosion to copper and substrate surfaces, bright and smooth copper surface after nickel stripping, and high peel strength of the secondary nickel plating layer, which can fully meet the requirements of the nickel stripping process for IC substrates.

[0141] In summary, this invention provides an IC substrate nickel stripping agent and its preparation and stripping methods. The IC substrate nickel stripping agent comprises core components such as a main reactant, a coordinating agent, a wetting agent, an accelerator, and a stabilizer. This IC substrate nickel stripping agent has three major advantages: First, it exhibits excellent nickel stripping speed at room temperature and low copper stripping speed, combining high-efficiency nickel stripping performance with non-corrosive copper properties; second, the peel strength of the secondary nickel plating layer after nickel stripping is high, meeting the reliability requirements of IC substrates; and third, the exposed copper surface after complete nickel stripping is bright and smooth, greatly facilitating re-nickel plating after repairs.

[0142] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A nickel stripping agent for IC substrates, characterized in that, It includes the following components by mass concentration: main reactant 3.0-8.0%, ligand 1.0-5.0%, wetting agent 1.0-5.0%, accelerator 1.0-5.0%, and stabilizer 0.5-2.5%; The main reactant is one or more of 1,1-dimethyl ethyl phenylperoxy acid, 1,1-dimethyl ethyl methylperoxy acid, and 1,1-dimethyl ethyl perisononanoic acid. The ligand is one or more of N,N-dimethylimidazolium-1-sulfonamide, N-cyclohexyl-p-toluenesulfonamide, and 2-acrylamido-2-methylpropanesulfonic acid; The wetting agent is one or more of 1H,1H,2H,2H-perfluorooctyl mercaptan, 1H,1H,2H,2H-perfluorodecyl mercaptan, and 5-fluoro-2-mercaptobenzyl alcohol. The accelerator is one or more of 2-amino-5-bromobenzoic acid, 4-amino-2,6-dimethylbenzoic acid, and 2-amino-3-methylbenzoic acid; The stabilizer is one or more of 2-mercapto-5-fluorobenzimidazole, 5-difluoromethoxy-2-mercapto-1H-benzimidazole, and 4-chloro-2-mercapto-6-(trifluoromethyl)benzimidazole.

2. The IC substrate nickel stripping agent according to claim 1, characterized in that, It includes the following components by mass concentration: main reactant 3.0-6.0%, ligand 1.0-3.0%, wetting agent 1.0-3.0%, accelerator 1.0-3.0%, and stabilizer 0.5-1.5%.

3. The IC substrate nickel stripping agent according to claim 2, characterized in that, It consists of the following components in the indicated mass concentrations: main reactant 3.0-6.0%, ligand 1.0-3.0%, wetting agent 1.0-3.0%, accelerator 1.0-3.0%, stabilizer 0.5-1.5%, and the balance being water.

4. The method for preparing the nickel stripping agent for IC substrates according to any one of claims 1-3, characterized in that, The process includes the following steps: Weigh the main reactant, complexing agent, wetting agent, accelerator, stabilizer and water in sequence and add them to the reaction vessel. Stir and mix at room temperature of 25-28℃ for 30-35 minutes to obtain the final product.

5. The method for removing nickel from an IC substrate using a nickel stripping agent according to any one of claims 1-3, characterized in that, The process includes the following steps: using the IC substrate nickel stripping agent according to any one of claims 1-3 to perform nickel stripping treatment on the IC substrate.

6. The method for removing nickel from IC substrates using the nickel stripping agent according to claim 5, characterized in that, The nickel stripping process involves immersing the IC carrier board in a pre-immersion tank using an IC carrier board nickel stripping agent, followed by ultrasonic-assisted treatment at an ultrasonic frequency of 28-40kHz and a power of 100-150W.

7. The method for removing nickel from IC substrates using the nickel stripping agent according to claim 5, characterized in that, The nickel stripping process is performed at a temperature of 25±1℃ and a linear speed of 3.0±0.2 m / min.

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