A copper plating and electroplating antioxidant and a preparation method thereof

Abstract

The application discloses a copper antioxidant and a preparation method thereof. The antioxidant contains the following components per liter: 0.5-1g of corrosion inhibitor, 2-6g of methanol, 1-5g of benzyl alcohol, 0.5-3g of 4-amino-3-hydroxybenzoic acid, 1.0-3g of polyphosphate, and the rest is water. The antioxidant is prepared by adding the above components into a container, adding water to 1L, stirring for 30 minutes at normal temperature, and adjusting pH to 4-6 by using a pH regulator. The copper antioxidant has a discoloration resistance time of 5-6 days. The corrosion inhibitor and related components have low content, and the wastewater treatment cost is low, so the application is easy to popularize. The removal of the antioxidant protection film is simple, and only the conventional pickling and brushing process is needed.

Description

TECHNICAL FIELD

[0001] The present application relates to PCB processing technical field, especially a kind of copper and electroplating copper antioxidant and preparation method thereof. BACKGROUND

[0002] In the current double-sided and multilayer PCB production process, during the operation of copper deposition, whole plate electroplating and pattern transfer, copper surface on the board and in the hole is prone to oxidation, which seriously affects the quality of the product of pattern transfer and pattern electroplating. Moreover, the increase of false points caused by oxidation of inner layer board seriously affects the test efficiency of AOI.

[0003] After general copper deposition and whole plate electroplating, the PCB is usually treated with 1-3% dilute sulfuric acid, dried at 75-85°C, and then placed on the rack or stacked, waiting for dry film or wet film printing for pattern transfer. In this process, the PCB needs to be placed for 1-2 days or even 3-4 days, which is easy to cause copper oxidation in the air. In addition, during the pretreatment of pattern transfer, the copper layer on the board surface is usually treated with "3% dilute sulfuric acid + polishing". The oxidation layer in the hole can only be treated by pickling, and small holes are difficult to achieve ideal results during the previous drying process. Therefore, the oxidation degree in small holes is more serious than that on the board surface, and only pickling cannot remove the stubborn oxidation layer. This may cause the PCB to be scrapped due to no copper in the hole after pattern electroplating and etching. In summary, with the development of the circuit board industry and the improvement of product quality, the scrapping of small holes due to oxidation and the low test efficiency of inner and outer layer AOI are problems that need to be solved in the PCB production process. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a kind of copper and electroplating copper antioxidant and preparation method thereof.

[0005] The technical solution of the present application is: a kind of copper and electroplating copper antioxidant, each liter of the antioxidant includes the following components:

[0006] Corrosion inhibitor 0.5-1g;

[0007] Methanol 2-6g;

[0008] Benzyl alcohol 1-5g;

[0009] 4-amino-3-hydroxybenzoic acid 0.5-3g;

[0010] Polyphosphate 1-3g;

[0011] The balance is water.

[0012] As a preferred, the chemical formula of the corrosion inhibitor is as follows:

[0013]

[0014] wherein R1, R2, R3 are hydrogen, amine group, halogen, hydroxyl.

[0015] As preferred, the corrosion inhibitor comprises 1-hydroxybenzotriazole hydrate, 1-aminobenzotriazole, 5-hydroxybenzotriazole, 5-aminobenzotriazole, 5-chlorobenzotriazole.

[0016] As preferred, the polyphosphate is at least one of sodium pyrophosphate and sodium tripolyphosphate.

[0017] As preferred, the mass ratio of the polyphosphate to the corrosion inhibitor is ≥2.

[0018] As preferred, the pH value of the antioxidant is 4-6.

[0019] As preferred, the pH value of the antioxidant is adjusted by dilute sulfuric acid and sodium hydroxide.

[0020] As preferred, the present application provides a preparation method of a copper deposition and electroplating copper antioxidant, comprising:

[0021] S1), adding 0.5-1g of the corrosion inhibitor, 2-6g of methanol, 1-5g of benzyl alcohol, 0.5-3g of 4-amino-3-hydroxybenzoic acid, and 1-3g of polyphosphate into a container;

[0022] S2), adding water into the container to 1L, then stirring at normal temperature for 30 minutes, and adjusting the pH value to 4-6 by dilute sulfuric acid and sodium hydroxide, so as to obtain the antioxidant.

[0023] The present application has the following advantages:

[0024] 1. The copper deposition and electroplating copper antioxidant has a discoloration resistance time of 5-6 days.

[0025] 2. The copper deposition and electroplating copper antioxidant has low content of related components, low wastewater treatment cost, and is easy to popularize.

[0026] 3. The anti-oxidation protective film generated by the present application is simple to remove, only requiring the conventional “pickling + brushing” process. DETAILED DESCRIPTION

[0027] The specific embodiments of the present application are further described as follows:

[0028] Example 1

[0029] The copper antioxidant provided by the embodiment contains the following components per liter of copper antioxidant: 5-amino benzotriazole 0.5 g, methanol 4 g, benzyl alcohol 2 g, 4-amino-3-hydroxybenzoic acid 1.5 g, and sodium pyrophosphate 1 g.

[0030] The preparation method is as follows:

[0031] 1) Each component is weighed according to the above mass number;

[0032] 2) The components weighed in step 1) are placed into a reactor, water is added to 1 L, then stirred at room temperature for 30 minutes, and diluted sulfuric acid is used to adjust the pH to 5, thereby obtaining the copper antioxidant.

[0033] After copper deposition, the test plate is immersed in the antioxidant solution at 35°C for 2 min, then taken out, washed with water and dried, and the copper surface discoloration under natural conditions for 1-7 days is recorded, and the test results are shown in Table 2.

[0034] Example 2

[0035] The copper antioxidant provided by the embodiment contains the following components per liter of copper antioxidant: 5-amino benzotriazole 0.5 g, methanol 4 g, benzyl alcohol 2 g, 4-amino-3-hydroxybenzoic acid 1.5 g, and sodium pyrophosphate 1 g.

[0036] The preparation method is as follows:

[0037] 1) Each component is weighed according to the above mass number;

[0038] 2) The components weighed in step 1) are placed into a reactor, water is added to 1 L, then stirred at room temperature for 30 minutes, and diluted sulfuric acid is used to adjust the pH to 5, thereby obtaining the copper antioxidant.

[0039] After copper deposition, the test plate is immersed in the antioxidant solution at 35°C for 2 min, then taken out, washed with water and dried, and the copper surface discoloration under natural conditions for 1-7 days is recorded, and the test results are shown in Table 2.

[0040] Comparative Example 1

[0041] Compared with Example 1, 5-amino benzotriazole is added to adjust to 0.8 g, and the others are the same as in Example 1.

[0042] Comparative Example 2

[0043] Compared with Example 1, 4-amino-3-hydroxybenzoic acid is not added, and the others are the same as in Example 1.

[0044] Comparative Example 3

[0045] Compared with Example 1, 5-amino benzotriazole is not added, and the others are the same as in Example 1.

[0046] Comparative Example 4

[0047] Compared with Example 1, 5-amino benzotriazole was added to adjust to 0.2 g, and other conditions were the same as Example 1.

[0048] Comparative Example 5

[0049] Blank group, no antioxidant treatment after copper deposition.

[0050] The specific differences are shown in Table 1.

[0051]

[0052] Table 2 Anti-discoloration results

[0053]

[0054]

[0055] From Example 1, 2 and Comparative Example 1 in Table 1 and Table 2, it can be seen that when the mass ratio of polyphosphate to corrosion inhibitor is < 2, the anti-discoloration time decreases significantly, and when the mass ratio of polyphosphate to corrosion inhibitor is ≥ 2, the anti-discoloration ability is more prominent. From Example 1 and Comparative Example 2, it can be seen that without adding 4-amino-3-hydroxybenzoic acid, the anti-discoloration time decreases significantly, indicating that 4-amino-3-hydroxybenzoic acid has the effect of extending the anti-discoloration time. From Example 1 and Comparative Examples 3 and 4, it can be seen that without adding corrosion inhibitor, the prepared antioxidant has almost no anti-discoloration ability. When the corrosion inhibitor is less than 0.5 g / L, the anti-discoloration ability decreases significantly, so the corrosion inhibitor should be higher than 0.5 g / L, so as to ensure that the anti-discoloration time reaches more than 5 days.

[0056] The above examples and descriptions in the specification are only to illustrate the principles and the best mode of the present application, and various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. An antioxidant for copper plating and electroplating, characterized in that: Each liter of the antioxidant comprises the following components: Corrosion inhibitor 0.5-1g; 2-6g of methanol; 1-5g of benzyl alcohol; 0.5-3g of 4-amino-3-hydroxybenzoic acid; Polyphosphate 1-3g; The remainder is water; The corrosion inhibitor is 5-aminobenzotriazole; The polyphosphate is at least one of sodium pyrophosphate and sodium tripolyphosphate; The mass ratio of the polyphosphate to the corrosion inhibitor is ≥2.

2. The anti-oxidant for copper plating and electroplating according to claim 1, characterized in that, The antioxidant has a pH value of 4-6.

3. The anti-oxidant for copper plating and electroplating according to claim 2, characterized in that, The antioxidant mentioned uses dilute sulfuric acid and sodium hydroxide to adjust the pH value.

4. A method for preparing the copper plating and electroplating antioxidant according to any one of claims 1-3, comprising: S1) Add 0.5-1g of corrosion inhibitor, 2-6g of methanol, 1-5g of benzyl alcohol, 0.5-3g of 4-amino-3-hydroxybenzoic acid, and 1-3g of polyphosphate to the container; S2) Add water to a container to 1L, stir at room temperature for 30 minutes, and adjust the pH value to 4-6 using dilute sulfuric acid and sodium hydroxide to obtain the antioxidant.

Images