Study On Surface Modification And Electroless Copper Plating Of PI Films

Surface modification of PI film to make it suitable for electroless copper plating-free palladium is the main purpose of the paper. Experimental research of this paper mainly includes three parts:the first part is the surface modification of PI film; the second part is the activation of PI film after surface modification; the last part is the electroless cooper plating of PET film after activation.Four ways of surface modification of PI film were used totally:1.laser treatment;2. plasma treatment;3. combined treatment using laser and plasma;4. alkaline hydrolysis treatment. The experimental results showed that in the experiment of electroless copper plating initiated by loaded silver particles, PI film after plasma modification was difficult to be loaded by silver particles and then obtain electroless copper plating layer; PI film after laser treatment, combined treatment using laser and plasma and alkaline hydrolysis treatment could load silver particles and obtain electroless copper plating layer. But the films treated by laser treatment and combined treatment using laser and plasma had poor binding force with electroless copper plating layer, and had been partly off washed by water. PI film after alkaline hydrolysis treatment had good binding force with electroless copper plating layer and could not rip off by tape.In the Alkaline hydrolysis modification, NaOH was selected as treatment agent. The effect of concentration of NaOH, time of hydrolysis modification and temperature of hydrolysis modification on hydrolysis modification were discussed, and the optimum values of the above influencing factors were determined:concentration of NaOH was20%(mass fraction), time of hydrolysis modification was60min, temperature of hydrolysis modification was30℃. FT-IR was used to prove that hydrolysis reaction was occurred on the surface of PI film and generated functional group like-COO-,-NH-, and ect. The droplets had good spreadability on the surface of PI film after alkaline hydrolysis modification,so it could be proved that PI film after alkaline hydrolysis modification had good hydrophilic and got electroless copper plating layer with good binding force after loading silver particles.In the activation experiments, AgNO3was selected as activator. The effect of concentration of AgNO3and time of activation on deposition rate of electroless copper and binding force between copper plating layer and PI film were discussed, and the optimum values of the above influencing factors were determined:concentration of AgN03was0.1g/L, time of activation was5min. SEM and binding force test were used to prove that AgNO3could not only catalyze electroless copper, but also greatly increase the binding force between electroless copper plating layer and PI film. In the aspect of increasing binding force between electroless copper plating layer and PI film, AgNO3had better effect than traditional electroless copper catalyst PdCl2.Electroless copper plating research on PI film:The effect of electroless copper plating additives such as2,2’-bipyridine, polyethylene glycol-6000, NiCl2and ect and the amount of the above various additives on quality of electroless copper plating layer was discussed. Ultimately the best dosages of all kinds of additives were determined:2,2’-bipyridine was0.4mg/L, polyethylene glycol-6000was2mg/L, NiCl2was2g/L. In the condition above, the electroless copper plating was compact, small and uniform with a good glossiness, toughness, heat impact resistance conductivity and binding force with PI film, being able to be applied in PCB industry and CCL industry.