High heat-resistant organic solderable preservative and preparation method thereof

Abstract

The application discloses a high-heat-resistance organic weldable protective agent and a preparation method thereof, and belongs to the technical field of surface treatment processes. The high-heat-resistance organic weldable protective agent comprises the following components in mass fractions: 5-10 parts of a composite film forming agent; 0.1-0.5 parts of an accelerator; 0.03-0.06 parts of a uniformizing agent; 0.002-0.006 parts of an organic solvent; and 0.1-0.3 parts of a stabilizer. The film obtained by the application is uniform and transparent, has strong weldability, good heat resistance, and good compatibility with gold surfaces, and is especially suitable for semi-nickel-gold and semi-OSP products, and the rework is simple. The alcohol and ester imidazole used in the application will not form a film on the gold surface, and will not affect the welding performance. The accelerator used in the application accelerates the formation of the film forming agent on the copper surface, does not corrode the equipment, and has a faster film forming speed. The uniformizing agent provided by the application can improve the uniformity of the film layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of surface treatment process, in particular, especially relates to a high heat-resistant organic solderability preservative and a preparation method thereof. BACKGROUND

[0002] High heat-resistant organic solderability preservative (HT-OSP) is related to the evolution of printed circuit board (PCB) surface treatment technology, the challenge of lead-free soldering process and the driving of environmental regulations. However, the traditional OSP technology has the following limitations.

[0003] Insufficient heat resistance. Early organic solderability preservatives (OSP) are mainly based on alkyl benzimidazole (ABI) compounds, which have a decomposition temperature of about 300℃, suitable for traditional lead soldering process, but easily decompose in lead-free high-temperature reflow soldering (such as above 260℃), leading to copper surface oxidation and affecting solderability.

[0004] Multiple reflow problems. Traditional OSP coatings are prone to degradation after multiple high-temperature soldering, which cannot meet the needs of high-density PCBs or complex electronic products that require multiple soldering.

[0005] Poor gold surface compatibility. Some OSPs may react with gold surface at high temperature, causing gold layer discoloration or corrosion, limiting their application in high-end packaging (such as BGA, LGA).

[0006] In addition, the promotion of lead-free soldering process, with the implementation of EU RoHS directive, the electronic industry has fully shifted to lead-free soldering, and the melting point of lead-free solder is higher (such as Sn-Ag-Cu alloy requires 260℃ or higher), which puts higher requirements on the heat resistance of PCB surface preservative. Traditional OSP cannot meet this demand, so it is urgent to develop HT-OSP with stronger heat resistance.

[0007] The research and development background of high heat-resistant organic solderability preservative is closely related to the trend of lead-free, environmental regulation constraints and high-density electronic manufacturing needs. The shortcomings of traditional OSP in heat resistance and process adaptability have promoted the exploration of new imidazole compounds, film forming mechanism optimization and additive technology. Future technology needs to further solve the problems of film stability, process compatibility and cost control to achieve wider application.

[0008] In view of the problems in the related art, no effective solution has been proposed so far. SUMMARY

[0009] In order to overcome the above problems, the present application aims to provide a high heat-resistant organic solderability preservative and a preparation method thereof, which aims to solve the problems of unstable organic solderability preservative film, poor process compatibility and high cost.

[0010] To this end, the specific technical solutions adopted by the present application are as follows:

[0011] According to one aspect of the present application, a high-heat-resistant organic solderable preservative is provided, which comprises the following components in mass fraction:

[0012] The composite film-forming agent is 5-10 parts;

[0013] The accelerator is 0.1-0.5 parts;

[0014] The uniformizing agent is 0.03-0.06 parts;

[0015] The organic solvent is 0.002-0.006 parts;

[0016] The stabilizer is 0.1-0.3 parts.

[0017] Further, the composite film-forming agent comprises imidazole alcohol compound and imidazole ester compound in a mass ratio of 1:1;

[0018] The imidazole alcohol compound is imidazole-2-methanol;

[0019] The imidazole ester compound is imidazole-2-ethyl formate.

[0020] Further, the accelerator is an amino piperidinol compound;

[0021] The amino piperidinol compound is 1-amino-4-piperidinol.

[0022] Further, the uniformizing agent is an indole carboxylic acid alcohol compound;

[0023] The indole carboxylic acid alcohol compound is 5,6-dihydroxyindole-2-carboxylic acid.

[0024] Further, the organic solvent is ethylene glycol monobutyl ether, and the operating temperature of the ethylene glycol monobutyl ether is 35-45℃, and the pH control range of the ethylene glycol monobutyl ether is 3.8-4.2.

[0025] Further, the stabilizer is o-nitrobenzoic acid.

[0026] According to another aspect of the present application, a preparation method of the high-heat-resistant organic solderable preservative is also provided, which comprises:

[0027] S1, mixing imidazole-2-methanol and imidazole-2-ethyl formate to obtain a composite film-forming agent;

[0028] S2, adding ethylene glycol monobutyl ether to the composite film-forming agent, dissolving the composite film-forming agent, and preparing a first mixed solution;

[0029] S3, the uniformizing agent and the accelerator are added into the first mixed solution respectively, and stirred uniformly to obtain a second mixed solution;

[0030] S4, the pH regulator is added into the second mixed solution, the pH value of the second mixed solution is adjusted to 3.8-4.2, and dilution is carried out at a temperature of 38-42 DEG C to obtain the high-heat-resistant organic solderable protective agent.

[0031] Further, the pH regulator is acetic acid and ammonia.

[0032] Further, the high-heat-resistant organic solderable protective agent is added in the following way:

[0033] 5ml of the second mixed solution is added per square meter.

[0034] Further, the test evaluation criteria of the high-heat-resistant organic solderable protective agent include the color difference index, the film forming speed index, the stability index and the reflow film forming discoloration index.

[0035] Compared with the prior art, the application has the following beneficial effects:

[0036] 1) The present application provides a composite film forming agent using imidazole alcohol and imidazole ester compounds, which changes the defect that traditional alkyl imidazole compounds are easily decomposed and invalid, and the decomposition residues generated by the decomposition of traditional alkyl imidazole substances at high temperature will cause welding, and the gold surface film forming in semi-nickel gold and semi-OSP products, and the alcohol and ester imidazole used in the present application greatly enhances the effect due to the change of functional groups, which not only does not form a film on the gold surface, but also does not affect the welding performance.

[0037] 2) The accelerator can accelerate the formation of the film forming agent on the copper surface, and the traditional accelerator uses halogen elements and copper ions to accelerate the formation of OSP film, which has a large environmental treatment pressure, and produces micro-corrosion on high-end products, especially on products with high precision, which is not conducive to large-area promotion and use, and the substance used in the present application will not corrode the equipment, and the film forming speed is faster than that of the previous accelerator.

[0038] 3) The uniformizing agent provided by the present application can improve the uniformity of the film layer, and the traditional OSP, especially the copper ion, has poor copper film uniformity, and the difference between the thickest and thinnest places is almost 0.15 microns, while the difference between the thickest and thinnest places obtained by using the present application is less than 0.02 microns. BRIEF DESCRIPTION OF DRAWINGS

[0039] The above characteristics, features and advantages of the present application and its implementation and method become more apparent and understandable in combination with the following description of the embodiments, which are described in detail in conjunction with the drawings. Herein is shown in a schematic diagram:

[0040] Figure 1 is a preparation method flow chart of a high-heat-resistant organic solderable preservative according to an embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the personnel in the technical field better understand the scheme of the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person of ordinary skill in the art without making creative labor are within the scope of protection of the present application.

[0042] According to an embodiment of the present application, a high-heat-resistant organic solderable preservative and a preparation method thereof are provided.

[0043] The present application will be further described in combination with the drawings and specific embodiments. According to an embodiment of the present application, a high-heat-resistant organic solderable preservative is provided, which comprises the following components in mass fraction:

[0044] 5-10 parts of a composite film forming agent;

[0045] 0.1-0.5 parts of a promoter;

[0046] 0.03-0.06 parts of a uniformizing agent;

[0047] 0.002-0.006 parts of an organic solvent;

[0048] 0.1-0.3 parts of a stabilizer.

[0049] In this optional embodiment, the high-heat-resistant organic solderable preservative comprises the following components in mass concentration: 5-10 g / L of a composite film forming agent, 0.1-0.5 g / L of a promoter, 30-60 mg / L of a uniformizing agent, 2-6 ml / L of an organic solvent, and 0.1-0.3 g / L of a stabilizer.

[0050] In this optional embodiment, the composite film forming agent comprises imidazole alcohol compound and imidazole ester compound in a mass ratio of 1:1;

[0051] The imidazole alcohol compound is imidazole-2-methanol;

[0052] The imidazole ester compound is imidazole-2-ethyl formate.

[0053] In this optional embodiment, the promoter is an amino piperidinol compound;

[0054] The amino piperidinol compound is 1-amino-4-piperidinol.

[0055] In the optional embodiment, the uniformizing agent is an indole carboxylic alcohol compound.

[0056] The indole carboxylic alcohol compound is 5,6-dihydroxyindole-2-carboxylic acid.

[0057] In the optional embodiment, the organic solvent is ethylene glycol monobutyl ether, and the operating temperature of the ethylene glycol monobutyl ether is 35-45℃, and the pH control range of the ethylene glycol monobutyl ether is 3.8-4.2.

[0058] In the optional embodiment, the stabilizing agent is o-nitrobenzoic acid.

[0059] According to another embodiment of the present application, as shown in Figure 1 the present application also provides a preparation method of the high-heat-resistant organic solderable preservative, and the preparation method comprises:

[0060] S1, mixing imidazole-2-methanol and imidazole-2-carboxylic acid ethyl ester with a mass concentration of more than 5 times to obtain a composite film forming agent;

[0061] S2, adding ethylene glycol monobutyl ether with a mass concentration of more than 5 times to the composite film forming agent to dissolve the composite film forming agent and prepare a first mixed solution;

[0062] S3, adding a uniformizing agent and an accelerator with a mass concentration of more than 5 times respectively to the first mixed solution, stirring uniformly to obtain a second mixed solution;

[0063] S4, taking 200 ml of the second mixed solution, adding a pH adjusting agent to the second mixed solution, adjusting the pH value of the second mixed solution to 3.8-4.2, and diluting to 1 L at a temperature of 38-42℃ to obtain the high-heat-resistant organic solderable preservative.

[0064] In the optional embodiment, the pH adjusting agent is acetic acid and ammonia water.

[0065] In the optional embodiment, the replenishment mode of the high-heat-resistant organic solderable preservative is:

[0066] 5 ml of the second mixed solution needs to be added per square meter.

[0067] In the optional embodiment, the test evaluation criteria of the high-heat-resistant organic solderable preservative include color difference index, film forming speed index, stability index, and reflow film forming discoloration index.

[0068] In the optional embodiment, the color difference index is excellent, which means that the OSP film is bright and has no watermark; the color difference index is good, which means that the OSP film is slightly bright, but has no watermark; the color difference index is poor, which means that there is a slight watermark and the film layer is slightly colored; and the color difference index is poor, which means that the coloring is serious and the watermark is obvious.

[0069] The upper film speed index excellent refers to a film thickness of 0.4-0.5 μm / min; the upper film speed index good refers to a film thickness of 0.3-0.4 μm / min (not including 0.4); the upper film speed index poor refers to a film thickness of 0.2-0.3 μm / min (not including 0.3); and the upper film speed index bad refers to a film thickness of 0.2 μm / min.

[0070] The stability index excellent refers to a use cycle of 8 TO (1 TO represents a cylinder opening amount required for adding a supplement liquid) and above; the stability index excellent refers to a use cycle of 8 TO and above; the stability index good refers to a use cycle of 6-8 TO (not including 8); the stability index poor refers to a use cycle of 4-6 TO (not including 6); and the stability index bad refers to a use cycle of 4 TO and below.

[0071] The reflux upper film discoloration index excellent refers to no discoloration for three times of reflux; the reflux upper film discoloration index good refers to slight discoloration for three times of reflux; the reflux upper film discoloration index poor refers to obvious red discoloration for three times of reflux; and the reflux upper film discoloration index bad refers to red discoloration for three times of reflux, and black substance is produced on the film surface.

[0072] The following further describes the specific embodiments of the present application in combination with examples and comparative examples:

[0073] Example 1

[0074] Imidazole-2-methanol 3 g / L, imidazole-2-ethyl formate 3 g / L, 1-amino-4-piperidinol 0.3 g / L, 5,6-dihydroxyindole-2-carboxylic acid 45 mg / L, ethylene glycol monobutyl ether 4 ml / L, o-nitrobenzoic acid 0.2 g / L;

[0075] pH 4.0, and the rest is deionized water;

[0076] The operation temperature is 40°C;

[0077] The time is 1 min;

[0078] According to Table 1, the experimental results of Example 1 are as follows: the color difference index is excellent, the upper film speed index is excellent, the stability is excellent, and the reflux upper film discoloration index is excellent.

[0079] Example 2

[0080] Imidazole-2-methanol 2.5 g / L, imidazole-2-ethyl formate 2.5 g / L, 1-amino-4-piperidinol 0.1 g / L, 5,6-dihydroxyindole-2-carboxylic acid 30 mg / L, ethylene glycol monobutyl ether 6 ml / L, o-nitrobenzoic acid 0.1 g / L;

[0081] pH 4.0, and the rest is deionized water;

[0082] The operation temperature is 40°C;

[0083] Time 1 min;

[0084] According to Table 1, the experimental results of Example 2 are: the color difference index is excellent, the film forming speed index is excellent, the stability is excellent, and the backflow film discoloration index is excellent.

[0085] Example 3

[0086] Imidazole-2-methanol 5 g / L, imidazole-2-carboxylic acid ethyl ester 5 g / L, 1-amino-4-piperidinol 0.5 g / L, 5,6-dihydroxyindole-2-carboxylic acid 30 mg / L, ethylene glycol monobutyl ether 2 ml / L, o-nitrobenzoic acid 0.3 g / L;

[0087] pH 4.0, and the balance is deionized water;

[0088] Operating temperature 40°C;

[0089] Time 1 min;

[0090] According to Table 1, the experimental results of Example 3 are: the color difference index is excellent, the film forming speed index is excellent, the stability is excellent, and the backflow film discoloration index is excellent.

[0091] Comparative Example 1

[0092] Imidazole-2-carboxylic acid ethyl ester 3 g / L, 1-amino-4-piperidinol 0.3 g / L, 5,6-dihydroxyindole-2-carboxylic acid 45 mg / L, ethylene glycol monobutyl ether 4 ml / L, o-nitrobenzoic acid 0.2 g / L;

[0093] pH 4.0, and the balance is deionized water;

[0094] Operating temperature 40°C;

[0095] Time 1 min;

[0096] Comparative Example 1 lacks the film former imidazole-2-methanol compared to the examples. According to Table 1, the experimental results of Comparative Example 1 are: the color difference index is good, the film forming speed index is poor, the stability is excellent, and the backflow film discoloration index is poor.

[0097] Comparative Example 2

[0098] Imidazole-2-methanol 3 g / L, 1-amino-4-piperidinol 0.3 g / L, 5,6-dihydroxyindole-2-carboxylic acid 45 mg / L, ethylene glycol monobutyl ether 4 ml / L, o-nitrobenzoic acid 0.2 g / L;

[0099] pH 4.0, and the balance is deionized water;

[0100] Operating temperature 40°C;

[0101] Time 1 min;

[0102] Comparative Example 2 lacks the film-forming agent ethyl imidazole-2-carboxylate compared to the examples, and according to Table 1, the experimental results of Comparative Example 2 are: color difference index is good, film-up speed index is good, stability is excellent, and backflow film discoloration index is good.

[0103] Comparative Example 3

[0104] Imidazole-2-methanol 3 g / L, ethyl imidazole-2-carboxylate 3 g / L, 5,6-dihydroxyindole-2-carboxylic acid 45 mg / L, ethylene glycol monobutyl ether 4 ml / L, o-nitrobenzoic acid 0.2 g / L;

[0105] pH 4.0, with the balance being deionized water;

[0106] Operating temperature 40°C;

[0107] Time 1 min;

[0108] Comparative Example 3 lacks the accelerator compared to the examples, and according to Table 1, the experimental results of Comparative Example 3 are: color difference index is good, film-up speed index is poor, stability is excellent, and backflow film discoloration index is poor.

[0109] Comparative Example 4

[0110] Imidazole-2-methanol 3 g / L, ethyl imidazole-2-carboxylate 3 g / L, 1-amino-4-piperidinol 0.3 g / L, ethylene glycol monobutyl ether 4 ml / L, o-nitrobenzoic acid 0.2 g / L;

[0111] pH 4.0, with the balance being deionized water;

[0112] Operating temperature 40°C;

[0113] Time 1 min;

[0114] Comparative Example 4 lacks the uniformizing agent compared to the examples, and the experimental results of Comparative Example 4 are: color difference index is good, film-up speed index is excellent, stability is excellent, and backflow film discoloration index is good.

[0115] Comparative Example 5

[0116] Imidazole-2-methanol 3 g / L, ethyl imidazole-2-carboxylate 3 g / L, 1-amino-4-piperidinol 0.3 g / L, 5,6-dihydroxyindole-2-carboxylic acid 45 mg / L, ethylene glycol monobutyl ether 4 ml / L, o-nitrobenzoic acid 0.2 g / L;

[0117] pH 4.0, with the balance being deionized water;

[0118] Operating temperature 40°C;

[0119] Time 1 min;

[0120] Comparative Example 5 lacks stabilizer compared with the examples, and the experimental results of Comparative Example 5 are: the color difference index is good, the film forming speed index is excellent, the stability is poor, and the backflow film color change index is good.

[0121]

[0122] In summary, by means of the above technical solutions of the present application, the present application can achieve a rate of 0.4-0.5 μm or more in 1 min, and the obtained film is uniform and transparent, has bright color and luster, has strong weldability, has a heat resistance temperature of 285°C, does not change color after three times of backflow, has good gold surface compatibility, is particularly suitable for semi-nickel gold and semi-OSP products, and has simple rework; the present application uses imidazole alcohol and imidazole ester compounds as the composite film forming agent, changes the defect of easy decomposition and failure of traditional alkyl imidazole compounds, and the decomposition residues produced by the decomposition of traditional alkyl imidazole substances at high temperature will cause welding, and the alcohol and ester imidazole used in the present application will not affect the welding performance because of the change of functional groups, not only will not form a film on the gold surface, but also will not affect the welding performance; the accelerator can accelerate the formation of the film forming agent on the copper surface, and the traditional accelerator uses halogen elements and copper ions to accelerate the formation of the OSP film, and these accelerators have great environmental treatment pressure, and will cause micro-corrosion on high-end products, especially on products with high precision, which is not conducive to large-area promotion and use, the substance used in the present application will not corrode the equipment, and the film forming speed is faster than that of the previous accelerator; the uniformizing agent provided by the present application can improve the uniformity of the film layer, and the traditional OSP, especially the copper ion, has poor copper film uniformity, and the difference between the thickest and thinnest parts is almost 0.15 microns, while the difference between the thickest and thinnest parts of the film obtained by the present application is less than 0.02 microns.

[0123] Although the present application has been disclosed with the above preferred embodiments, the embodiments are only for illustration and do not limit the present application, and those skilled in the art can make some changes and modifications without departing from the spirit and scope of the present application, and the protection scope claimed by the present application should be subject to the description of the claims.

Claims

1. A high heat-resistant organic solderable preservative, characterized by comprising: The high-heat-resistant organic solderable preservative comprises the following components by mass fraction: 5-10 parts of a composite film forming agent; the composite film forming agent comprises imidazole alcohol compound and imidazole ester compound in a mass ratio of 1:1; the imidazole alcohol compound is imidazole-2-methanol; the imidazole ester compound is imidazole-2-carboxylic acid ethyl ester; 0.1-0.5 parts of an accelerator; the accelerator is amino piperidine alcohol compound; the amino piperidine alcohol compound is 1-amino-4-piperidinol; 0.03-0.06 parts of a uniformizing agent; the uniformizing agent is indole carboxylic acid alcohol compound; the indole carboxylic acid alcohol compound is 5,6-dihydroxyindole-2-carboxylic acid; 0.002-0.006 parts of an organic solvent; 0.1-0.3 parts of a stabilizer; the stabilizer is o-nitrobenzoic acid.

2. The high heat-resistant organic solderability preservative according to claim 1, characterized by, The organic solvent is ethylene glycol monobutyl ether, and the operating temperature of the ethylene glycol monobutyl ether is 35-45°C; the pH control range of the ethylene glycol monobutyl ether is 3.8-4.

2. The high-heat-resistant organic solderable preservative comprises the following components by mass fraction: 5-10 parts of a composite film forming agent; the composite film forming agent comprises imidazole alcohol compound and imidazole ester compound in a mass ratio of 1:1; the imidazole alcohol compound is imidazole-2-methanol; the imidazole ester compound is imidazole-2-carboxylic acid ethyl ester; 0.1-0.5 parts of an accelerator; the accelerator is amino piperidine alcohol compound; the amino piperidine alcohol compound is 1-amino-4-piperidinol; 0.03-0.06 parts of a uniformizing agent; the uniformizing agent is indole carboxylic acid alcohol compound; the indole carboxylic acid alcohol compound is 5,6-dihydroxyindole-2-carboxylic acid; 0.002-0.006 parts of an organic solvent; 0.1-0.3 parts of a stabilizer; the stabilizer is o-nitrobenzoic acid. The organic solvent is ethylene glycol monobutyl ether, and the operating temperature of the ethylene glycol monobutyl ether is 35-45°C; the pH control range of the ethylene glycol monobutyl ether is 3.8-4.2.

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