CN110117791B - Binding force promoter for brown oxide liquid of high-density interconnection printed circuit board - Google Patents

Abstract

The invention belongs to the field of printed circuit board manufacturing, and particularly provides a binding force promoter for a high-density interconnection printed circuit board browning liquid and a browning treatment liquid containing the binding force promoter, which are used for overcoming the defect that benzotriazole and derivatives thereof exist as a browning liquid component. The invention adopts tetrazole compound as binding force promoter, and the prepared browning treatment fluid has the following advantages: 1) The copper carrying quantity is high and can reach 60g/L; 2) Environmental friendliness, such as tetrazole violet can be used as a medical intermediate; 3) The stability is good, no pungent smell exists, and the ionic liquid is not easy to volatilize; taking tetrazole violet as an example, the melting point of the tetrazole violet is 247-249 ℃ which is far higher than 98.5 ℃ of BTA, and the solution is not easy to produce precipitate residues after the browning treatment; 4) The organic matter dosage is small, the reaction condition is mild, and the temperature operation window is wide; 5) The prepared printed circuit board has good tearing strength, good moisture resistance and acid resistance, and no pink ring.

Description

A bonding accelerator for browning liquid of high-density interconnected printed circuit boards

Technical field

The invention belongs to the field of printed circuit board manufacturing, and relates to a pre-treatment liquid for interlayer lamination of printed circuit boards. Specifically, it is a bonding force accelerator for browning liquid of high-density interconnected printed circuit boards, and a bonding force accelerator containing the bonding force. Accelerator browning solution.

Background technique

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 interconnection between various components. As printed circuit boards develop in the direction of being light, thin, and high-density, higher requirements are placed on equipment and production processes, 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 High Density Interconnect (HDI) manufacturing technology, which has attracted more and more attention from the market. The printed circuit industry has entered the era of high-frequency and high-speed interconnection and is paying more and more attention to the surface roughness of electronic circuits and the bonding strength between layers. Any-layer high-density connection board (Any-layer HDI) is an HDI technology manufactured using the Sequential Buildup method. Its production process is relatively cumbersome, especially the lamination process has very strict quality control indicators. , such as the density of holes on any-layer is higher, and the number of high-temperature (>200°C) lamination during the production process exceeds 5 times. Therefore, the browning film can withstand multiple and long-term high-temperature hot-pressing impacts and is acid-leaching resistant. A key factor to ensure lamination performance, otherwise it will lead to failure of inter-layer interconnection. 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.

Commonly used methods to improve the bonding strength between layers (including copper and resin) mainly include black oxide, micro-etching, brown oxide, etc. At present, acid/ The hydrogen peroxide-based micro-etching chemical inner layer browning treatment process of copper surface. The browning process has the advantages of simple operation, high efficiency, low cost, and mild process conditions. The board surface after browning treatment has strong oxidation resistance and can effectively inhibit "Pink ring" and other characteristics, the browning process has become the main process for the inner layer production of printed circuit boards. The browning liquid mainly contains acid corrosive liquid, bonding force accelerator, oxidant and other main components. In the browning process, an organic copper oxide film is formed on the surface of the inner copper circuit of the printed circuit board. During lamination, this organic copper oxide film is combined with The resin undergoes a curing cross-linking reaction, which can provide better interfacial bonding between layers.

At present, browning liquid usually contains a large amount of triazole and its derivatives, copper ions, arsenic and other substances. Careless wastewater treatment of browning liquid will bring great harm to the ecological environment; three of them Nitrogen and its derivatives can easily cause hypoxia and eutrophication in the water environment, and can cause cancer and damage blood functional systems after human exposure. Therefore, the development of new, efficient, and environmentally friendly browning liquid has broad market prospects.

Contents of the invention

The object of the present invention is to provide a bonding force accelerator for browning liquid of high-density interconnected printed circuit boards, and a bonding agent containing the The browning treatment liquid of force accelerator is used to improve the bonding force between the inner copper surface and the prepreg to obtain a printed circuit board with excellent comprehensive performance.

In order to achieve the above objects, the technical solutions adopted by the present invention are as follows:

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

Among them, X ₁ , X ₂ , X _{3 ,} and

Further, the binding force accelerator is a phenyltetrazole compound, and its molecular structure is:

Among them, X ₁ , X ₂ , X _{3 ,} and

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

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

Further, the binding force accelerator 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 liquid containing the above-mentioned binding force accelerator, including: H ₂ SO ₄ : 50 to 120 g/L, H ₂ O ₂ : 5 to 50 g/L, HCl: 0 to 80 mg/L, CuSO ₄ ·5H ₂ O: 0~60g/L, corrosion inhibitor: 1~20g/L, binding accelerator: 1~10g/L, and deionized water.

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

Furthermore, 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 the corrosion inhibitor is: 5-15g/L, so 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; using tetrazole compounds as the binding force accelerator, the browning treatment liquid is configured to obtain Chemical treatment fluid has the following advantages:

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

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

3) Good stability, no irritating odor, and the 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 the 98.5°C of BTA. After browning treatment, the solution is not prone to precipitation residue;

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

5) The printed circuit board produced has good tear strength, moisture resistance, and acid resistance, and no pink circles will appear; the thermal shock resistance is qualified and the peel strength is good. The copper brown surface shows a uniform micro-erosion structure when observed under an electron microscope.

Detailed ways

The technical solution of the present invention will be further elaborated below in conjunction with the examples:

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

Acid washing-water washing-alkaline degreasing-water washing-pre-soaking-browning-pure water washing-drying-pressing.

(1) Pickling: Use 3%-5% dilute sulfuric acid as cleaning agent to wash away the metal oxides loaded on the copper surface at 25-40°C;

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

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

(4) Water washing: rinse with tap water and then wash repeatedly with deionized water at room temperature to remove the alkaline washing liquid;

(5) Pre-soaking: Put the above-mentioned washed PCB board into the pre-soaking tank (temperature 30°C, time 30 seconds), so that the PCB board can quickly form a browning film after entering the browning tank, and at the same time prevent contamination by other metal ions The materials are brought into the browning tank;

(6) Browning: Browning is the core of this process. The pre-soaked PCB board is browned using a horizontal spray method in a PVC browning tank. 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 there is no residual browning liquid on the PCB board;

(8) Drying: Place it in the oven and control the temperature to 100°C for drying;

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

The preparation method of browning liquid described in the present invention includes 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 to the reactor, and stir evenly.

Example 1

A kind of browning treatment liquid for printed circuit boards. The composition of the browning treatment liquid is: H ₂ SO ₄ : 80g/L, H ₂ O ₂ : 10g/L, HCl: 10 mg/L, CuSO ₄ ·5H ₂ O : 25mg/L, binding accelerator: tetrazole violet 2g/L, 1-phenyl-5-mercapto-1H-tetrazole 1g/L, corrosion inhibitor: cyproconazole 5g/L, deionized water added to 1L; In this example, the browning temperature is 35°C, the browning time is 45 s, and the peel strength is measured with reference to the IPC-TM-650 standard method.

After testing, the copper content of the browning liquid can reach 55g/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℃ There was no delamination or board explosion after 6 impacts under the condition of 10 seconds per impact; the peeling strength between the copper surface and the prepreg after lamination was 5.1b/in.

Example 2

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

After testing, the copper content of the browning liquid can reach 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℃ There was no delamination or board explosion after 6 impacts under the condition of 10 seconds per impact; the peel strength of the copper surface and the prepreg after lamination was 4.9b/in.

Example 3

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

After testing, the copper content of the browning liquid 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℃ There was no delamination or board explosion after 6 impacts under the condition of 10 seconds per impact; the peel strength of the copper surface and the prepreg after lamination was 5.4b/in.

Example 4

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

After testing, the copper content of the browning liquid can reach 54g/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℃ There was no delamination or board explosion after 6 impacts under the condition of 10 seconds per impact; the peel strength of the copper surface and the prepreg after lamination was 5.4b/in.

The above are only specific embodiments 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 features disclosed, or All method or process steps, except mutually exclusive features and/or steps, may be combined in any way.

Claims (2)

1. The high-density interconnection printed circuit board browning treatment fluid is characterized by comprising the following components: h ₂ SO ₄ ：50～120g/L，H ₂ O ₂ ：5～50g/L，HCl：0～80mg/L，CuSO ₄ ·5H ₂ O: 0-60 g/L, corrosion inhibitor: 1-20 g/L, binding force promoter: 1-10 g/L and deionized water;

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

2. The high-density interconnect printed circuit board browning treatment fluid of claim 1, wherein said H ₂ SO ₄ The concentration of (2) is: 80-110g/L, H ₂ O ₂ The concentration of the corrosion inhibitor is 10-20 g/L, and the concentration of the corrosion inhibitor is as follows: 5-15g/L, wherein the concentration of the binding force promoter is 3-6g/L.