CN110117791A - A kind of binding force promotor for holes on high density interconnected printed circuit board brownification liquid - Google Patents

Abstract

The invention belongs to the field of printed circuit board manufacturing, and specifically provides a binding force promoter for browning liquid of high-density interconnected printed circuit boards, and a browning treatment liquid containing the binding force promoter, to overcome benzo The deficiencies of triazole and its derivatives as components of browning solution. The present invention adopts tetrazole compounds as the binding force promoter, and the browning treatment solution prepared has the following advantages: 1) high copper loading, which can be as high as 60g/L; 2) environment-friendly, such as tetrazolium violet can be used as a pharmaceutical intermediate Use; 3) Good stability, no irritating odor, and ionic liquids are not easy to volatilize; taking tetrazolium violet as an example, its melting point is 247-249°C, which is much higher than 98.5°C of BTA, and the solution after browning treatment is not easy to produce precipitation residues 4) The amount of organic matter is small, the reaction conditions are mild, and the temperature operating window is wide; 5) The printed circuit board has good tear strength, good moisture resistance and acid resistance, and no pink circle will appear.

Description

A kind of cohesive force promoter for browning solution of high-density interconnected printed circuit board

technical field

The invention belongs to the field of printed circuit board manufacturing, and relates to a pretreatment liquid for interlayer lamination of printed circuit boards, in particular to a binding force accelerator for browning liquid of high-density interconnected printed circuit boards, and includes the binding force Accelerated browning treatment fluid.

Background technique

The printed circuit board is an important electronic component. It provides support for the installation and fixation of various electronic components, and at the same time shoulders the important task of circuit communication between various components. With the development of printed circuit boards in the direction of lightness, thinness and high density, higher requirements are brought to equipment and production technology, especially the use of electroplating hole filling and blind hole stacking technology to realize any layer on the printed circuit board (PCB). The electrical interconnection between two or more layers becomes the High Density Interconnect (HDI) manufacturing technology, which is getting more and more attention from the market. The printed circuit industry has entered the era of high-frequency and high-speed interconnection and pays more and more attention to the surface roughness of electronic circuits and the bonding force between layers. Any-layer HDI is a HDI technology manufactured by Sequential Buildup method. The production process is relatively cumbersome, especially the lamination process has very strict quality control indicators. , For example, the hole density on the Any-layer is higher, and the number of high-temperature (>200°C) laminations exceeds 5 times during the production process. The key factor to ensure the lamination performance, otherwise it will lead to the failure of the interconnection between layers. Therefore, the interlayer lamination process is directly related to the reliability of any layer of high-density connection boards, and the copper surface roughening process before interlayer lamination directly determines the reliability of the printed circuit board after lamination.

The methods commonly used to improve the bonding force between layers (including between copper and resin) mainly include black oxide, micro-etching, brown oxide, etc. At present, the pre-treatment process of HDI lamination often uses acid/ Hydrogen peroxide-based copper surface micro-etching type chemical inner layer browning treatment process, the browning process has the advantages of simple operation, high efficiency, low cost, mild process conditions, strong oxidation resistance of the board surface after browning treatment, and can effectively inhibit "Pink ring" and other characteristics, the current browning process has become the main process for the inner layer of printed circuit boards. The browning solution mainly contains acid corrosion solution, binding force promoter, oxidant and other main components. In the browning process, an organic copper oxide film layer is formed on the surface of the inner copper circuit of the printed circuit board. When laminating, this layer of organic copper oxide film layer and The resin undergoes a curing cross-linking reaction, which can provide better interfacial bonding force for interlayer lamination.

At present, the browning solution usually contains a large amount of triazole and its derivatives, copper ions and pyrrole, etc. If the wastewater treatment of the browning solution is slightly careless, it will bring great harm to the ecological environment; three of them Nitroxazole and its derivatives can easily lead to hypoxia and eutrophication in the water environment, and can easily cause cancer and damage the blood function system after human exposure; therefore, the development of new, efficient, and environmentally friendly browning solutions has broad market prospects.

Contents of the invention

The purpose of the present invention is to address the shortcomings of benzotriazole and its derivatives as browning liquid components, to provide a binding force accelerator for high-density interconnected printed circuit board browning liquid, and to include the combination The browning treatment solution of the force accelerator is used to improve the bonding force between the inner layer copper surface and the prepreg, and obtain a printed circuit board with excellent comprehensive performance.

To achieve the above object, the technical scheme adopted in the present invention is as follows:

A binding force accelerator for browning solution of high-density interconnected printed circuit boards, characterized in that, said binding force accelerator is a tetrazole compound, and its molecular structure is:

Wherein, X ₁ , X ₂ , X ₃ , and X ₄ are all substituents, specifically mercapto-SH, carboxyl-COOH, sulfonic acid-SO3H, amino-NH, phenyl or naphthyl.

Further, the binding force promoter is a phenyltetrazolium compound, and its molecular structure is:

Wherein, X ₁ , X ₂ , X ₃ , and X ₄ are all substituents, specifically mercapto-SH, carboxyl-COOH, sulfonic acid-SO3H, amino-NH, phenyl or naphthyl.

Further, the binding force promoter is tetrazolium violet, and its molecular structure is:

Further, the binding force promoter is 2,5 diphenyl-3-(4 styrylphenyl) tetrazolium chloride, and its molecular structure is:

Further, the binding force promoter is 2,3 diphenyl-5-(4 methoxyphenyl) tetrazolium chloride, and its molecular structure is:

Further, the binding force promoter is 1-phenyl-5-mercapto-1H-tetrazole, and its molecular structure is:

A browning treatment solution containing the above binding force promoter, comprising: H ₂ SO ₄ : 50-120 g/L, H ₂ O ₂ : 5-50 g/L, HCl: 0-80 mg/L, CuSO ₄ ·5H ₂ O: 0~60g/L, corrosion inhibitor: 1~20g/L, binding force promoter: 1~10g/L, and deionized water.

Further, the binding force promoter is tetrazolium violet, 1-phenyl-5-mercapto-1H-tetrazole, 2,5 diphenyl-3-(4 styrylphenyl) tetrazolium chloride One or more of azoles, 2,3 diphenyl-5-(4 methoxyphenyl) tetrazolium chloride.

Further, the concentration of H ₂ SO ₄ is 80-110g/L%, the concentration of H ₂ O ₂ is 10-20g/L, and the concentration of corrosion inhibitor is 5-15g/L. The concentration of the binding force promoter is 3-6g/L.

The beneficial effects of the present invention are:

The invention provides a binding force accelerator for browning liquid of high-density interconnected printed circuit boards, and a browning treatment liquid containing the binding force accelerator; a tetrazole compound is used as the binding force accelerator, and the browning treatment liquid is configured to brown Chemical treatment fluid has the following advantages:

1) High copper loading, up to 60g/L;

2) Environmentally friendly, such as tetrazolium violet can be used as a pharmaceutical intermediate;

3) Good stability, no irritating smell, ionic liquid is not easy to volatilize; taking tetrazolium violet as an example, its melting point is 247-249°C, which is much higher than 98.5°C of BTA, and the solution is not easy to produce precipitation residue after browning treatment;

4) The amount of organic matter is small, the reaction conditions are mild, and the temperature operating window is wide (can be used at high and low temperatures);

5) The prepared printed circuit board has good tear strength, good moisture resistance, good acid resistance, and no pink circle; the heat shock resistance is qualified and the peel strength is good, and the copper browning surface shows a uniform micro-etched structure by electron microscope observation.

Detailed ways

Below in conjunction with embodiment technical scheme of the present invention is further elaborated:

In the present invention, the browning process technical route is as follows:

Pickling - water washing - alkaline degreasing - water washing - presoaking - browning - pure water washing - drying - pressing.

(1) pickling: use 3%-5% dilute sulfuric acid as a cleaning agent, and wash away the metal oxides loaded on the copper surface under the condition of 25-40°C;

(2) Water washing: first rinse with tap water, then repeatedly wash with deionized water at room temperature until the lotion is basically neutral;

(3) Alkaline degreasing: use an alkaline degreasing agent to wash the above washed PCB board under the condition of 40-60°C. Its purpose is to effectively remove grease and other pollutants on the copper surface and prepare for later browning;

(4) Washing: use deionized water to wash repeatedly at room temperature to remove alkaline lotion after rinsing with tap water;

(5) Pre-soaking: Put the above-mentioned washed PCB board into the pre-soaking tank (temperature 30°C, time 30s), so that the browning film can be quickly formed after the PCB board enters the browning tank, and at the same time, other metal ions are prevented from being polluted into the browning tank;

(6) Browning: Browning is the core of this process. In the PVC browning tank, the method of horizontal spraying is used to brown the pre-impregnated PCB board. The browning temperature is 30-40°C and the browning time is 30 -50s;

(7) Pure water washing: wash repeatedly with deionized water at room temperature until the PCB board has no residual browning solution;

(8) Drying: Put it in an oven and control the temperature at 100°C for drying;

(9) Lamination: Laminate the browned copper clad laminate with the prepreg, and test its peel strength.

The preparation method of browning liquid described in the present invention comprises the following steps:

(1) Add deionized water, HCl, H ₂ SO ₄ , CuSO ₄ 5H2O to the reactor in sequence and stir evenly until the copper sulfate is completely dissolved;

(2) Continue to add the required amount of corrosion inhibitor, binding force promoter and H ₂ O ₂ into the reactor, and stir evenly.

Example 1

A printed circuit board browning treatment solution, the composition of the browning treatment solution is: H ₂ SO ₄ : 80g/L, H ₂ O ₂ : 10g/L, HCl: 10mg/L, CuSO ₄ 5H ₂ O : 25mg/L, binding force promoter: tetrazolium violet 2g/L, 1-phenyl-5-mercapto-1H-tetrazole 1g/L, corrosion inhibitor: cyclaconazole 5g/L, deionized water was added to 1L; in this example, the browning temperature is 35°C, the browning time is 45s, and the peel strength is measured with reference to the IPC-TM-650 standard method.

After testing, the browning liquid can carry 55g/L of copper, and the copper surface can get a uniform and rough surface after browning treatment, and has stable bonding force and excellent heat resistance with the prepreg, 288 ℃ Under the condition of each impact for 10s, there is no delamination or bursting phenomenon after 6 impacts; the peel strength between the copper surface and the prepreg after pressing is 5.1b/in.

Example 2

A printed circuit board browning treatment solution, the composition of the browning treatment solution is: H ₂ SO ₄ : 100g/L, H ₂ O ₂ : 16g/L, HCl: 80mg/L, CuSO ₄ 5H ₂ O : 200mg/L, binding force promoter: tetrazole violet 1.5g/L, 1-phenyl-5-mercapto-1H-tetrazole 1g/L, 2,3 diphenyl-5-(4 methoxyphenyl ) tetrazolium chloride 0.5g/L, corrosion inhibitor: cyclaconazole 1g/L, 1-methyl-4-butylbenzimidazole 2g/L, 3,5-dimethyl-2-mercaptobenzo Imidazole is 2g/L, and deionized water is added to 1L; in this example, the browning temperature is 40°C, and the browning time is 30s.

After testing, the browning solution has a copper loading capacity of 59g/L, and the copper surface can obtain a uniform and rough surface after browning treatment, and has stable bonding force and excellent heat resistance with the prepreg, 288 ℃ Under the condition of each impact for 10s, there is no delamination or bursting phenomenon after 6 impacts; the peel strength between the copper surface and the prepreg after pressing is 4.9b/in.

Example 3

A printed circuit board browning treatment solution, the composition of the browning treatment solution is: H ₂ SO ₄ : 110g/L, H ₂ O ₂ : 25g/L, HCl: 30mg/L, CuSO ₄ 5H ₂ O : 60mg/L, binding force promoter: tetrazole violet 1.5g/L, 1-phenyl-5-mercapto-1H-tetrazole 1g/L, 2,3 diphenyl-5-(4 methoxyphenyl ) tetrazolium chloride 1g/L, corrosion inhibitor: cyproconazole 1g/L, 1-methyl-4-butylbenzimidazole 2g/L, 3,5-dimethyl-2-mercaptobenzimidazole Add 1 g/L of corrosion inhibitor to 1 L of deionized water; in this example, the browning temperature is 35°C, and the browning time is 35s.

It has been tested that the copper loading of the browning solution can reach 60g/L, and the copper surface can obtain a uniform and rough surface after browning treatment, and has stable bonding force and excellent heat resistance with the prepreg, 288 ℃ Under the condition of each impact for 10s, there is no delamination or bursting phenomenon after 6 impacts; the peel strength between the copper surface and the prepreg after pressing is 5.4b/in.

Example 4

A printed circuit board browning treatment solution, the composition of the browning treatment solution is: H ₂ SO ₄ : 100g/L, H ₂ O ₂ : 15g/L, HCl: 25mg/L, CuSO ₄ 5H ₂ O : 60mg/L, binding force promoter: 1-phenyl-5-mercapto-1H-tetrazole 1g/L, 2,5 diphenyl-3-(4 styrylphenyl) tetrazolium chloride 0.1 g/L, tetrazole violet 0.5g/L, 2,3 diphenyl-5-(4 methoxyphenyl) tetrazolium chloride 0.5g/L, corrosion inhibitor: 1-methyl-4 butyl Benzimidazole 1.5g/L, 3,5-dimethyl-2-mercaptobenzimidazole 1.5g/L, cyclaconazole 2g/L, add deionized water to 1L; in this example, the browning temperature is 35 ℃, browning time 40s.

After testing, the browning liquid can carry up to 54g/L of copper, and the copper surface can get a uniform and rough surface after browning treatment, and has stable bonding force and excellent heat resistance with the prepreg, 288 ℃ Under the condition of each impact for 10s, there is no delamination or bursting phenomenon after 6 impacts; the peel strength between the copper surface and the prepreg after pressing is 5.4b/in.

The above is only a specific embodiment of the present invention. Any feature disclosed in this specification, unless specifically stated, can be replaced by other equivalent or alternative features with similar purposes; all the disclosed features, or All method or process steps may be combined in any way, except for mutually exclusive features and/or steps.

Claims (9)

1. a binding force accelerator for high-density interconnection printed circuit board browning liquid, it is characterized in that, described binding force accelerator is a tetrazole compound, and its molecular structure is: Wherein, X ₁ , X ₂ , X ₃ , and X ₄ are all substituents, specifically mercapto-SH, carboxyl-COOH, sulfonic acid-SO3H, amino-NH, phenyl or naphthyl. 2. by the described binding promotor of claim 1, it is characterized in that, described binding promotor is phenyltetrazolium compound, and its molecular structure is: Wherein, X ₁ , X ₂ , X ₃ , and X ₄ are all substituents, specifically mercapto-SH, carboxyl-COOH, sulfonic acid-SO3H, amino-NH, phenyl or naphthyl. 3. According to the described binding force promoter of claim 2, it is characterized in that, the described binding force promoter is tetrazolium violet. 4. The binding force promoter according to claim 2, characterized in that, the binding force promoter is 2,5 diphenyl-3-(4 styrylphenyl) tetrazolium chloride. 5. The binding force promoter according to claim 2, characterized in that, the binding force promoter is 2,3 diphenyl-5-(4 methoxyphenyl) tetrazolium chloride. 6. The binding force promoter according to claim 2, characterized in that, the binding force promoter is 1-phenyl-5-mercapto-1H-tetrazole. 7. A browning treatment solution comprising the binding force promoter according to claim 1, comprising: H ₂ SO ₄ : 50-120 g/L, H ₂ O ₂ : 5-50 g/L, HCl: 0-80 mg/L L, CuSO ₄ ·5H ₂ O: 0-60g/L, corrosion inhibitor: 1-20g/L, binding force promoter: 1-10g/L, and deionized water. 8. by the described browning treatment liquid of claim 7, it is characterized in that, described cohesion promoter is tetrazolium violet, 1-phenyl-5-mercapto-1H-tetrazole, 2,5 diphenyl- One or more of 3-(4-styrylphenyl) tetrazolium chloride and 2,3-diphenyl-5-(4-methoxyphenyl) tetrazolium chloride. 9. According to the browning treatment liquid described in claim ₇ , it is characterized in that the concentration of said _H2SO4 is: _80-110g /L%, the concentration of H2O2 is ₁₀ ～20g/L, and the concentration of said slow The concentration of the etchant is 5-15g/L, and the concentration of the binding force promoter is 3-6g/L.