Cyanide-free gold plating method for preparing ACF (anisotropic conductive film) conductive gold spheres

A technology of cyanide-free gold plating and conductive gold balls, which is applied in the direction of liquid chemical plating, metal material coating process, coating, etc., can solve the problems affecting the social safety of operators, less adsorption amount, easy to decompose, etc., and achieves wide application Foreground, improvement of binding force, effect of large adsorption capacity

Active Publication Date: 2015-02-11
SHENZHEN FISHER NEW MATERIALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the traditional process of preparing conductive gold balls is to plate gold after electroless nickel plating on the surface of the microspheres. The nickel plating process includes pretreatment processes such as roughening, sensitization, and activation. Impurity ions such as tin ions will be introduced to affect the plating solution. stability, and strong acid solution will be used, which will affect the safety of operation. At the same time, the colloidal palladium used for activation is unstable and easy to decompose
Cyanide is used as a complexing agent in the traditional electroless gold plating process. Cyanide is a highly toxic drug controlled by the state, which seriously pollutes the environment and affects the safety of operators and society.
In the process of gold plating on the surface of nickel balls, in the initial stage of gold plating, the replacement reaction will introduce nickel ions, which will affect the stability of the gold plating solution.
The preparation of conductive gold spheres mentioned in Chinese patent CN102658071A makes the surface of polymer microspheres adsorb gold sol, and then chemically gold-plates. The gold sol used for adsorption has larger particles, less adsorption, and uneven adsorption. The adsorption of gold sol is mainly physical adsorption, the binding force is not good, and the coating is easy to fall off

Method used

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  • Cyanide-free gold plating method for preparing ACF (anisotropic conductive film) conductive gold spheres
  • Cyanide-free gold plating method for preparing ACF (anisotropic conductive film) conductive gold spheres
  • Cyanide-free gold plating method for preparing ACF (anisotropic conductive film) conductive gold spheres

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] Add 20 g of polystyrene microspheres and 20 g of dichloroethane into a three-necked bottle equipped with a stirrer, ultrasonically disperse, stir and swell at 300 rpm for 1 hour, and obtain swollen polystyrene microspheres. Add 20g of methylal to a three-necked flask equipped with a stirrer, a dropping funnel, a thermometer, and a condenser with a calcium chloride drying tube, and add 35g of sulfuryl chloride dropwise within 1 hour at 25°C. , and then reacted for 1 hour to obtain the reacted mixed solution. Pour the mixed solution into the swollen polystyrene microspheres, stir at 300 rpm for 3 hours, then add 8 g of anhydrous zinc chloride powder into the reaction system, and stir at 40° C. for 8 hours. Centrifuge and wash to obtain chloromethylated polystyrene microspheres. The chloromethylated polystyrene microsphere of gained is joined in the three-neck bottle that the NaOH solution of 100ml 5% is housed, in Bu 4 Under the condition that NOH is used as a catalyst,...

Embodiment 2

[0053] Ultrasonic dispersion of 25 g of polystyrene microspheres in 25 g of dichloroethane was then added to a three-necked bottle equipped with a stirrer, and stirred and swelled at 300 rpm for 1 hour to obtain swollen polystyrene microspheres. In a three-necked flask equipped with a stirrer, a dropping funnel, a thermometer and a condenser tube equipped with a calcium chloride drying tube, add 22g of methylal, and drop 39g of sulfuryl chloride within 1 hour at 25°C. , and then reacted for 1 hour to obtain the reacted mixed solution. The mixture was poured into the swollen polystyrene microspheres and stirred at 300 rpm for 3 hours. Then add 10 g of anhydrous zinc chloride powder into the above reaction system, and stir at 40° C. for 8 hours. Centrifuge and wash to obtain chloromethylated polystyrene microspheres. The chloromethylated polystyrene microsphere of gained is joined in the three-neck bottle that the NaOH solution of 150ml 5% is housed, in Bu 4 Under the con...

Embodiment 3

[0057] Ultrasonic dispersion of 30 g of polystyrene microspheres in 30 g of dichloroethane was added to a three-necked bottle equipped with a stirrer, and stirred and swelled at 300 rpm for 1 hour to obtain swollen polystyrene microspheres. Add 25g of methylal to a three-necked flask equipped with a stirrer, a dropping funnel, a thermometer, and a condenser with a calcium chloride drying tube, and add 45g of sulfuryl chloride dropwise within 1 hour at 25°C. , and then reacted for 1 hour to obtain the reacted mixed solution. Pour the mixed solution into the swollen polystyrene microspheres, stir at 300 rpm for 3 hours, then add 12 g of anhydrous zinc chloride powder into the reaction system, and stir at 40° C. for 8 hours. Centrifuge and wash to obtain chloromethylated polystyrene microspheres. The chloromethylated polystyrene microsphere of gained is joined in the three-neck bottle that 200ml 10% NaOH solution is housed, in Bu 4 Under the condition that NOH is used as ca...

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Abstract

The invention relates to a cyanide-free gold plating method for preparing ACF (anisotropic conductive film) conductive gold spheres, which comprises the following steps: 1. preparing swollen polystyrene microspheres; 2. preparing chloromethylated polystyrene microspheres; 3. adding 2,3-dimercaptopropanol into the chloromethylated polystyrene microsphere alkaline solution to prepare mercapto polystyrene microspheres; 4. preparing polystyrene microspheres of which the surface is adsorbed with gold ions; 5. dispersing the polystyrene microspheres of which the surface is adsorbed with gold ions in a reducing solution to obtain polystyrene microspheres of which the surface is adsorbed with simple substance gold; and 6. dispersing the polystyrene microspheres of which the surface is adsorbed with simple substance gold in a cyanide-free gold plating solution to obtain the conductive gold spheres. The method is simple and easy to implement; the obtained gold coating has the advantage of favorable binding force with the substrate and has fine and compact crystals; and the method avoids introducing impurity ions, avoids using cyanides, is safe to operate and can implement large-scale production.

Description

technical field [0001] The invention belongs to the field of preparation of conductive microspheres, in particular to a cyanide-free gold plating method for preparing ACF (anisotropic conductive film) conductive gold balls. Background technique [0002] With the development of light, thin, and small electronic devices, traditional tin-lead soldering can no longer meet the requirements. At present, anisotropic conductive film (ACF) has been widely used in the connection of liquid crystal displays and flexible circuit boards. Conductive gold balls are the core part of ACF. In order to make them have excellent electrical conductivity and mechanical properties and reduce costs, they are chemically plated with gold on the surface of polymer microspheres. [0003] At present, the traditional process of preparing conductive gold balls is to plate gold after electroless nickel plating on the surface of the microspheres. The nickel plating process includes pretreatment processes such...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C18/44C23C18/20
CPCC23C18/20C23C18/44
Inventor 杨常武龚火烘刘呈贵孔翔雨赵昌后谭林清肖仁亮
Owner SHENZHEN FISHER NEW MATERIALS CO LTD
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