High-corrosion-resistance bright chemical nickel plating solution and integrated circuit nickel plating process

Abstract

The invention discloses a high-corrosion-resistance bright chemical nickel plating solution and an integrated circuit nickel plating process, and relates to the field of the electronic core industry. The high-corrosion-resistance bright chemical nickel plating solution comprises a water-soluble nickel salt, boric acid, sodium citrate, malic acid, N, N-dimethyl formamide and a solvent. According to the present invention, the water-soluble nickel salt, the boric acid, the sodium citrate, the malic acid, the N, N '-bis (2-ethoxyl) ethylenediamine, the N, N-diethyl propargyl amine formate, the saccharin sodium salt and the reducing agent are co-matched so as to easily refine nickel crystal grains and promote the uniform deposition of the nickel crystal grains, such that the nickel crystal grains can be uniformly dispersed, and the nickel crystal grains can be uniformly dispersed; according to the invention, the brightening of the plating layer can be realized, the porosity of the plating layer is reduced, and the permeation of a corrosive medium is favorably blocked, so that the corrosion resistance of the integrated circuit substrate is improved.

Description

Technical Field

[0001] This application relates to the core electronics industry, and in particular to a high corrosion-resistant bright electroless nickel plating solution and its nickel plating process for integrated circuits. Background Technology

[0002] As a crucial carrier connecting chips to external circuits, the performance of the integrated circuit substrate directly affects the stability, reliability, and lifespan of the entire integrated circuit. Electroless nickel plating on the integrated circuit substrate is a common step in integrated circuit manufacturing. An ideal electroless nickel plating layer for an integrated circuit substrate must simultaneously meet the following key indicators: 1. The plating layer must possess excellent corrosion resistance, capable of resisting the penetration of corrosive media such as moisture, acids, and alkalis in the external environment for a long time, preventing substrate corrosion failure; 2. The plating surface must have good gloss to ensure the accuracy of subsequent packaging processes and reduce circuit connection problems caused by surface defects. Summary of the Invention

[0003] To balance the corrosion resistance and brightness of the coating, this application provides a high corrosion-resistant and bright electroless nickel plating solution and its integrated circuit nickel plating process.

[0004] Firstly, the high corrosion-resistant bright electroless nickel plating solution provided in this application adopts the following technical solution: A highly corrosion-resistant bright electroless nickel plating solution includes water-soluble nickel salts, boric acid, sodium citrate, malic acid, N,N'-bis(2-hydroxyethyl)ethylenediamine, N,N-diethylpropynylamine formate, sodium saccharin, and a reducing agent.

[0005] In some specific embodiments, the mass concentration of the water-soluble nickel salt is 20-30 g / L, the mass concentration of the boric acid is 5-25 g / L, the mass concentration of the sodium citrate is 10-40 g / L, the mass concentration of the malic acid is 5-30 g / L, the mass concentration of the N,N'-bis(2-hydroxyethyl)ethylenediamine is 5-15 g / L, the mass concentration of the N,N-diethylpropynylamine formate is 0.05-0.20 g / L, the mass concentration of the sodium saccharin is 0.5-2.0 g / L, and the mass concentration of the reducing agent is 20-40 g / L.

[0006] In this application, the high corrosion-resistant bright electroless nickel plating solution, through the combined action of water-soluble nickel salts, boric acid, sodium citrate, malic acid, N,N'-bis(2-hydroxyethyl)ethylenediamine, N,N-diethylpropynylamine formate, sodium saccharin, and reducing agents, is beneficial for refining nickel grains and promoting uniform deposition of nickel grains. This results in a brighter coating and reduces the porosity of the coating, which helps to block the penetration of corrosive media, thereby improving the corrosion resistance of the integrated circuit substrate.

[0007] In some preferred embodiments, the water-soluble nickel salt has a mass concentration of 25-30 g / L, the boric acid has a mass concentration of 20-25 g / L, the sodium citrate has a mass concentration of 15-20 g / L, the malic acid has a mass concentration of 20-25 g / L, the N,N'-bis(2-hydroxyethyl)ethylenediamine has a mass concentration of 5-10 g / L, the N,N-diethylpropynylamine formate has a mass concentration of 0.1-0.15 g / L, the sodium saccharin has a mass concentration of 1.5-2.0 g / L, and the reducing agent has a mass concentration of 35-40 g / L.

[0008] In this application, the preferred mass concentrations of water-soluble nickel salt, boric acid, sodium citrate, malic acid, N,N'-bis(2-hydroxyethyl)ethylenediamine, N,N-diethylpropynylamine formate, sodium saccharin, and reducing agent are within the above-mentioned ranges. This can further improve the deposition efficiency of the nickel layer while ensuring the uniformity, corrosion resistance, and brightness of the coating, and at the same time ensure that the internal stress of the coating does not increase, which is beneficial to preventing brittleness problems caused by rapid deposition efficiency.

[0009] In some specific embodiments, the water-soluble nickel salt is a combination of nickel sulfate and nickel aminosulfonate, wherein the mass concentration ratio of nickel sulfate to nickel aminosulfonate is (3-4):1.

[0010] In this application, the water-soluble nickel salt is a combination of nickel sulfate and nickel aminosulfonate, which is beneficial to further improve the toughness of the coating and reduce the brittleness of the coating.

[0011] In some specific embodiments, the reducing agent is sodium hypophosphite.

[0012] In some specific embodiments, the high corrosion-resistant bright electroless nickel plating solution also includes sodium 3-S-isothiourea propane sulfonate and sodium N,N-dimethyl-dithioformamide propane sulfonate.

[0013] In some specific embodiments, the mass concentration of sodium 3-S-isothiourea propane sulfonate is 2-5 mg / L, and the mass concentration of sodium N,N-dimethyl-dithioformamide propane sulfonate is 0.5-2 g / L.

[0014] In this application, appropriate amounts of sodium 3-S-isothiourea propane sulfonate and sodium N,N-dimethyl-dithioformamide propane sulfonate are added to a high corrosion-resistant bright electroless nickel plating solution. Through the synergistic effect of sodium 3-S-isothiourea propane sulfonate and sodium N,N-dimethyl-dithioformamide propane sulfonate, the nickel deposition rate can be further improved, while taking into account the corrosion resistance, brightness and toughness of the coating.

[0015] Secondly, the nickel plating process for integrated circuits provided in this application adopts the following technical solution: A nickel plating process for integrated circuits includes the following steps: The integrated circuit substrate is pretreated to remove dirt and grease from the surface of the substrate, resulting in a pretreated integrated circuit substrate. The pretreated integrated circuit substrate is nickel-plated using any of the above-mentioned high corrosion-resistant bright electroless nickel plating solutions.

[0016] In some specific implementations, the nickel plating temperature is 80-90℃ and the nickel plating time is 15-60 minutes.

[0017] In summary, this application includes at least the following beneficial technical effects: (1) In this application, the high corrosion-resistant bright electroless nickel plating solution, through the combined action of water-soluble nickel salts, boric acid, sodium citrate, malic acid, N,N'-bis(2-hydroxyethyl)ethylenediamine, N,N-diethylpropynylamine formate, sodium saccharin and reducing agent, is conducive to refining nickel grains and promoting uniform deposition of nickel grains, which can achieve brightening of the coating and reduce the porosity of the coating, which is conducive to blocking the penetration of corrosive media, thereby improving the corrosion resistance of integrated circuit substrates.

[0018] (2) In this application, the mass concentrations of water-soluble nickel salt, boric acid, sodium citrate, malic acid, N,N'-bis(2-hydroxyethyl)ethylenediamine, N,N-diethylpropynylamine formate, sodium saccharin and reducing agent are controlled within the preferred range. This can further improve the deposition efficiency of the nickel layer while ensuring the uniformity, corrosion resistance and brightness of the coating. At the same time, it ensures that the internal stress of the coating does not increase, which is beneficial to prevent the brittleness problem caused by the fast deposition efficiency.

[0019] (3) In this application, an appropriate amount of sodium 3-S-isothiourea propane sulfonate and sodium N,N-dimethyl-dithioformamide propane sulfonate are added to the high corrosion-resistant bright electroless nickel plating solution. Through the synergistic effect of sodium 3-S-isothiourea propane sulfonate and sodium N,N-dimethyl-dithioformamide propane sulfonate, the nickel deposition rate can be further improved. At the same time, the corrosion resistance, brightness and toughness of the coating are taken into account. Detailed Implementation

[0020] The following section provides further explanation of this application in conjunction with specific experiments. Example

[0021]

Example 1

[0022]

Example 2

[0023]

Example 3

[0024]

Example 4

[0025]

Example 5

[0026]

Example 6

[0027]

Example 7

[0028] Comparative Example Comparative Example 1 A chemical nickel plating solution is prepared from nickel sulfate, nickel aminosulfonate, hydroxyethylidene diphosphonic acid, sodium citrate, lactic acid, N,N'-bis(2-hydroxyethyl)ethylenediamine, N,N-diethylpropynylamine formate, sodium saccharin, sodium hypophosphite, and deionized water, wherein the mass concentrations of the above components are as follows: Nickel sulfate: 15 g / L; Nickel aminosulfonate: 5 g / L; Hydroxyethylidene diphosphonic acid: 5 g / L; Sodium citrate: 40 g / L; Lactic acid: 5g / L; N,N'-Bis(2-hydroxyethyl)ethylenediamine: 5 g / L; N,N-Diethylpropynylamine formate: 0.20 g / L; Sodium saccharin: 0.5 g / L; Sodium hypophosphite: 20g / L.

[0029] Comparative Example 2 A chemical nickel plating solution is prepared from nickel sulfate, nickel aminosulfonate, boric acid, sodium citrate, malic acid, polyethylene glycol 200, N,N-diethylpropynylamine formate, p-toluenesulfonamide, sodium hypophosphite, and deionized water, wherein the mass concentrations of the above components are as follows: Nickel sulfate: 15 g / L; Nickel aminosulfonate: 5 g / L; Boric acid: 5g / L; Sodium citrate: 40 g / L; Malic acid: 5g / L; Polyethylene glycol 200: 5 g / L; N,N-Diethylpropynylamine formate: 0.20 g / L; p-Toluenesulfonamide: 0.5 g / L; Sodium hypophosphite: 20g / L.

[0030] Comparative Example 3 A chemical nickel plating solution differs from [Example 6] in that it also contains sodium 3-S-isothiourea propane sulfonate and sodium N,N-dimethyl-dithiocarbamate propane sulfonate. The mass concentration of sodium 3-S-isothiourea propane sulfonate is 2 mg / L, and the mass concentration of sodium N,N-dimethyl-dithiocarbamate propane sulfonate is 5 g / L.

[0031] Comparative Example 4 A chemical nickel plating solution, differing from [Example 6] in that it also contains 2-aminothiazole and sodium N,N-dimethyl-dithiocarbamate propane sulfonate, with the mass concentration of 2-aminothiazole being 2 mg / L and the mass concentration of sodium N,N-dimethyl-dithiocarbamate propane sulfonate being 2 g / L.

[0032] Comparative Example 5 A chemical nickel plating solution, which differs from [Example 6] in that it also contains sodium 3-S-isothiourea propane sulfonate, with a mass concentration of 2 mg / L.

[0033] Comparative Example 6 A chemical nickel plating solution, which differs from [Example 6] in that it also contains sodium N,N-dimethyl-dithiocarbamate propane sulfonate, with a mass concentration of 2 g / L.

[0034] Application examples A nickel plating process for integrated circuits includes the following steps: The integrated circuit substrate is pretreated to remove dirt and grease from the surface of the substrate, resulting in a pretreated integrated circuit substrate. High corrosion-resistant bright electroless nickel plating solution is used to perform nickel plating on the pretreated integrated circuit substrate. The nickel plating temperature is 80-90℃ and the nickel plating time is 15-60min.

[0035] Performance testing (1) Plating rate test: The plating thickness of each group of nickel-plated integrated circuit substrates was measured using an XDL-232 X-ray fluorescence thickness gauge. Ten points were selected for testing for each sample, and the average value was taken. The plating rate is expressed as the plating thickness per unit time. The preparation method of the nickel-plated integrated circuit substrate samples is as follows: S1. The integrated circuit substrate is pretreated to remove dirt and grease from the substrate surface to obtain a pretreated integrated circuit substrate; the pretreated integrated circuit substrate is subjected to electroless nickel plating using the chemical nickel plating solutions in each embodiment and comparative example. The nickel plating temperature is 85℃ and the nickel plating time is 20min.

[0036] (2) Coating roughness test: The surface roughness Ra of each group of nickel-plated integrated circuit substrates was tested using a TR300 surface roughness meter. Ten points were selected for testing each sample, and the average value was taken. The lower the roughness, the smoother and flatter the coating surface, and the better the brightness. The preparation method of the nickel-plated integrated circuit substrate samples is as follows: S1. The integrated circuit substrate is pretreated to remove dirt and grease from the substrate surface to obtain a pretreated integrated circuit substrate; the pretreated integrated circuit substrate is then subjected to electroless nickel plating using the chemical nickel plating solutions in each embodiment and comparative example. The nickel plating temperature is 85℃ and the nickel plating time is 20min.

[0037] (3) Neutral Salt Spray Test: The eZ-908 salt spray chamber was used to conduct salt spray tests on each group of nickel-plated integrated circuit substrates. The concentration of the sodium chloride solution used in the salt spray test was (50±5) g / L, the pH was 6.5-7.2, and the temperature of the test chamber was (35±2)℃. The test was conducted at 80cm intervals. 2 The salt spray deposition rate was 2 mL / h. The test sample was placed at a 45° angle to the vertical direction and sprayed continuously for 24 hours. After the spraying, the sample was cleaned with deionized water and air-dried. The surface of the coating was observed for darkening or rust spots. The absence of darkening or rust spots indicated good corrosion resistance of the coating. The preparation method of the nickel-plated integrated circuit substrate sample is as follows: S1. The integrated circuit substrate was pretreated to remove dirt and grease from the substrate surface to obtain a pretreated integrated circuit substrate. The pretreated integrated circuit substrate was then electroless nickel plating using the chemical nickel plating solutions from the examples and comparative examples. The electroless nickel plating temperature was 85℃, and the electroless nickel plating thickness was controlled to be 10±0.5μm.

[0038] (4) Toughness test: After nickel plating, each group of integrated circuit substrates was placed in a -20℃ environment for 168 hours. After returning to room temperature, a 200g steel ball was dropped from a position of 50cm onto the plating layer of each group of nickel-plated integrated circuit substrates, and the appearance of cracks in the plating layer was observed. The preparation method of the nickel-plated integrated circuit substrate samples is as follows: S1. The integrated circuit substrate was pretreated to remove dirt and grease from the substrate surface to obtain a pretreated integrated circuit substrate; the pretreated integrated circuit substrate was electroless nickel plating using the chemical nickel plating solutions in each example and comparative example, with the electroless nickel plating temperature at 85℃ and the electroless nickel plating thickness controlled at 10±0.5μm.

[0039] Table 1 Based on the test data in Example 1, Comparative Examples 1-2, and Table 1, it can be seen that in this application, the high corrosion-resistant bright electroless nickel plating solution, through the combined use of water-soluble nickel salts, boric acid, sodium citrate, malic acid, N,N'-bis(2-hydroxyethyl)ethylenediamine, N,N-diethylpropynylamine formate, sodium saccharin, and reducing agents in a specific ratio, is conducive to obtaining a coating that balances corrosion resistance, brightness, and toughness.

[0040] Based on the test data in Examples 1-5 and Table 1, it can be seen that in this application, by controlling the mass concentrations of water-soluble nickel salt, boric acid, sodium citrate, malic acid, N,N'-bis(2-hydroxyethyl)ethylenediamine, N,N-diethylpropynylamine formate, sodium saccharin, and reducing agent within the preferred range, the deposition efficiency of the nickel layer can be further improved while ensuring the uniformity, corrosion resistance, and brightness of the coating. At the same time, it ensures that the internal stress of the coating does not increase and prevents brittleness problems caused by rapid deposition efficiency.

[0041] Based on the test data from Examples 3-4, Examples 6-7, Comparative Examples 3-6, and Table 1, it can be seen that adding appropriate amounts of sodium 3-S-isothiourea propane sulfonate and sodium N,N-dimethyl-dithioformamide propane sulfonate to a high corrosion-resistant bright electroless nickel plating solution can further improve the nickel deposition rate through the synergistic effect of sodium 3-S-isothiourea propane sulfonate and sodium N,N-dimethyl-dithioformamide propane sulfonate, while also taking into account the corrosion resistance, brightness, and toughness of the coating.

[0042] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A highly corrosion-resistant bright electroless nickel plating solution, characterized in that: It includes water-soluble nickel salts, boric acid, sodium citrate, malic acid, N,N'-bis(2-hydroxyethyl)ethylenediamine, N,N-diethylpropynylamine formate, sodium saccharin, and reducing agents.

2. The high corrosion-resistant bright electroless nickel plating solution according to claim 1, characterized in that: The water-soluble nickel salt has a mass concentration of 20-30 g / L, the boric acid has a mass concentration of 5-25 g / L, the sodium citrate has a mass concentration of 10-40 g / L, the malic acid has a mass concentration of 5-30 g / L, the N,N'-bis(2-hydroxyethyl)ethylenediamine has a mass concentration of 5-15 g / L, the N,N-diethylpropynylamine formate has a mass concentration of 0.05-0.20 g / L, the sodium saccharin has a mass concentration of 0.5-2.0 g / L, and the reducing agent has a mass concentration of 20-40 g / L.

3. The high corrosion-resistant bright electroless nickel plating solution according to claim 2, characterized in that: The water-soluble nickel salt has a mass concentration of 25-30 g / L, the boric acid has a mass concentration of 20-25 g / L, the sodium citrate has a mass concentration of 15-20 g / L, the malic acid has a mass concentration of 5-10 g / L, the N,N'-bis(2-hydroxyethyl)ethylenediamine has a mass concentration of 8-12 g / L, the N,N-diethylpropynylamine formate has a mass concentration of 0.1-0.15 g / L, the sodium saccharin has a mass concentration of 1.5-2.0 g / L, and the reducing agent has a mass concentration of 35-40 g / L.

4. The high corrosion-resistant bright electroless nickel plating solution according to claim 2, characterized in that: The water-soluble nickel salt is a combination of nickel sulfate and nickel aminosulfonate, wherein the mass concentration ratio of nickel sulfate to nickel aminosulfonate is (3-4):

1.

5. The high corrosion-resistant bright electroless nickel plating solution according to claim 1, characterized in that: The reducing agent used is sodium hypophosphite.

6. A high corrosion-resistant bright electroless nickel plating solution according to any one of claims 1-5, characterized in that: The high corrosion-resistant bright electroless nickel plating solution also includes sodium 3-S-isothiourea propane sulfonate and sodium N,N-dimethyl-dithiocarbamate propane sulfonate.

7. The high corrosion-resistant bright electroless nickel plating solution according to claim 5, characterized in that: The sodium 3-S-isothiourea propane sulfonate has a mass concentration of 2-5 mg / L, and the sodium N,N-dimethyl-dithioformamide propane sulfonate has a mass concentration of 0.5-2 g / L.

8. A nickel plating process for integrated circuits, characterized in that: Includes the following steps: The integrated circuit substrate is pretreated to remove dirt and grease from the surface of the substrate, resulting in a pretreated integrated circuit substrate. The high corrosion-resistant bright electroless nickel plating solution described in any one of claims 1-7 is used to perform nickel plating on the pretreated integrated circuit substrate.

9. The nickel plating process for integrated circuits according to claim 8, characterized in that: The nickel plating temperature is 80-90℃, and the nickel plating time is 15-60 minutes.

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